Form Designer Events in Blazor PDF Viewer

20 Mar 202522 minutes to read

The Blazor PDF Viewer provides built-in support for handling form field-related events through the Form Designer feature. These events allow developers to track and customize the behavior of form fields, such as adding, removing, selecting, resizing, and modifying properties.

Event List

Below are the key events provided by the Form Designer to handle form field interactions in the PDF Viewer.

Event Name	Description
FormFieldAdding	Triggered before a new form field is added, allowing validation before insertion.
FormFieldAdded	Triggered when a form field is added to the PDF document.
FormFieldDeleted	Triggered when a form field is removed from the document.
FormFieldClick	Triggered when a user clicks on a form field while designer mode is off.
FormFieldDoubleClick	Triggered when a form field is double-clicked.
FormFieldSelected	Triggered when a form field is selected.
FormFieldUnselected	Triggered when a form field is unselected.
FormFieldResized	Triggered when a form field is resized.
ValidateFormFields	Triggered when form fields are validated.
FormFieldFocusIn	Triggered when focus enters a form field.
FormFieldFocusOut	Triggered when focus leaves a form field.
FormFieldMouseEnter	Triggered when the mouse hovers over a form field.
FormFieldMouseLeave	Triggered when the mouse leaves a form field.
FormFieldPropertyChanged	Triggered when a form field’s properties are modified.
IsDesignerModeChanged	Triggered when the designer mode state changes in the PDF Viewer.
FormFieldsExporting	Triggered before form fields are exported, allowing customization of the export process.
FormFieldsImporting	Triggered before form fields are imported, allowing validation or modifications.
FormFieldsExported	Triggered when form fields are successfully exported.
FormFieldsImported	Triggered when form fields are successfully imported.
FormFieldsExportFailed	Triggered when form fields export operation fails.
FormFieldsImportFailed	Triggered when form fields import operation fails.

FormFieldAdding Event

FormFieldAdding event is triggered before a form field addition starts in the SfPdfViewer2 component.

Additionally, the event provides a Cancel property, which can be set to true to prevent the form field from being added to the document conditionally.

Event Arguments

The FormFieldAdding event provides FormFieldAddEventArgs, which contains properties like Field (form field details), PageNumber (target page), and Cancel (to prevent addition).

@using Syncfusion.Blazor;
@using Syncfusion.Blazor.SfPdfViewer;

<SfPdfViewer2 Height="100%" Width="100%" DocumentPath="@DocumentPath">
    <PdfViewerEvents FormFieldAdding="@OnFormFieldAdding"></PdfViewerEvents>
</SfPdfViewer2>

@code {
    private string DocumentPath = "wwwroot/data/events.pdf";
    void OnFormFieldAdding(FormFieldAddEventArgs args)
    {
        // Access details about the adding form field
        Console.WriteLine($"Form Field being added: {args.Field.Name}");
        args.Cancel = true; // Prevents the form field from being added
        // Additional processing logic
    }
}

By setting args.Cancel = true;, developers can conditionally prevent the addition of form fields based on custom logic.

FormFieldAdded Event

FormFieldAdded event is triggered whenever a new form field is added to the PDF document. It allows developers to monitor the addition of form fields and apply default properties or validations.

Event Arguments

The FormFieldAdded event provides FormFieldAddedEventArgs, which includes properties like Field (details of the added field) and PageNumber (where the field was added). Developers can use these properties to monitor or modify the added form fields.

@using Syncfusion.Blazor;
@using Syncfusion.Blazor.SfPdfViewer;

<SfPdfViewer2 Height="100%" Width="100%" DocumentPath="@DocumentPath">
    <PdfViewerEvents FormFieldAdded="@OnFormFieldAdded"></PdfViewerEvents>
</SfPdfViewer2>

@code {
    private string DocumentPath = "wwwroot/data/events.pdf";
    void OnFormFieldAdded(FormFieldAddedEventArgs args)
    {
        // Access details about the added form field
        Console.WriteLine($"Form Field added: {args.Field.Name}");
        // Additional processing logic
    }
}

FormFieldDeleted Event

FormFieldDeleted event is triggered when a form field is removed from the document. It can be used to ensure proper cleanup and prevent accidental deletions.

Event Arguments

The FormFieldDeleted event provides FormFieldDeletedEventArgs, which contains properties like Field (deleted field details) and PageNumber. This event helps track and manage field deletions.

@using Syncfusion.Blazor;
@using Syncfusion.Blazor.SfPdfViewer;

<SfPdfViewer2 Height="100%" Width="100%" DocumentPath="@DocumentPath">
    <PdfViewerEvents FormFieldDeleted="@OnFormFieldDeleted"></PdfViewerEvents>
</SfPdfViewer2>

@code {
    private string DocumentPath = "wwwroot/data/events.pdf";

    void OnFormFieldDeleted(FormFieldDeletedEventArgs args)
    {
        // Access details about the deleted form field
        Console.WriteLine($"Form field deleted: {args.Field.Name}");

        // Implement additional logic, such as logging or UI updates
    }
}

FormFieldClick Event

FormFieldClick is triggered when a user clicks on a form field while designer mode is off. This event can be used to display tooltips, highlight fields, or open settings.

Event Arguments

The FormFieldClick event provides FormFieldClickArgs, containing FormField (clicked field details). It enables actions like highlighting fields or opening settings.

@using Syncfusion.Blazor;
@using Syncfusion.Blazor.SfPdfViewer;

<SfPdfViewer2 Height="100%" Width="100%" DocumentPath="@DocumentPath">
    <PdfViewerEvents FormFieldClick="@OnFormFieldClicked"></PdfViewerEvents>
</SfPdfViewer2>

@code {
    private string DocumentPath = "wwwroot/data/events.pdf";
    void OnFormFieldClicked(FormFieldClickArgs args)
    {
        // Access details about the clicked form field
        Console.WriteLine($"Form Field clicked: {args.FormField.Name}");
        // Additional processing logic
    }
}

FormFieldDoubleClick Event

FormFieldDoubleClick is triggered when a form field is double-clicked. This event is useful for triggering additional actions.

Event Arguments

The FormFieldDoubleClick event provides FormFieldDoubleClickEventArgs, which includes Field (double-clicked field details). It is useful for triggering additional actions when a field is double-clicked.

@using Syncfusion.Blazor;
@using Syncfusion.Blazor.SfPdfViewer;

<SfPdfViewer2 Height="100%" Width="100%" DocumentPath="@DocumentPath">
    <PdfViewerEvents FormFieldDoubleClick="@OnFormFieldDoubleClicked"></PdfViewerEvents>
</SfPdfViewer2>

@code {
    private string DocumentPath = "wwwroot/data/events.pdf";

    void OnFormFieldDoubleClicked(FormFieldDoubleClickEventArgs args)
    {
        // Access details about the double clicked form field
        Console.WriteLine($"Form field double clicked: {args.Field.Name}");

        // Implement additional logic, such as logging or UI updates
    }
}

FormFieldSelected Event

FormFieldSelected is triggered when a form field is selected. It can be used to show additional options or highlight the selected field.

Event Arguments

The FormFieldSelected event provides FormFieldSelectedEventArgs, which contains Field (selected field details) and PageNumber. This event helps in handling field selection and UI updates.

@using Syncfusion.Blazor;
@using Syncfusion.Blazor.SfPdfViewer;

<SfPdfViewer2 Height="100%" Width="100%" DocumentPath="@DocumentPath">
    <PdfViewerEvents FormFieldSelected="@OnFormFieldSelected"></PdfViewerEvents>
</SfPdfViewer2>

@code {
    private string DocumentPath = "wwwroot/data/events.pdf";

    void OnFormFieldSelected(FormFieldSelectedEventArgs args)
    {
        // Access details about the selected form field
        Console.WriteLine($"Form field selected: {args.Field.Name}");

        // Implement additional logic, such as logging or UI updates
    }
}

FormFieldUnselected Event

FormFieldUnselected is triggered when a selected form field is unselected. This event helps in resetting UI elements or hiding additional options.

Event Arguments

The FormFieldUnselected event provides FormFieldUnselectedEventArgs, which includes Field (unselected field details). It helps in resetting UI elements or hiding additional options.

@using Syncfusion.Blazor;
@using Syncfusion.Blazor.SfPdfViewer;

<SfPdfViewer2 Height="100%" Width="100%" DocumentPath="@DocumentPath">
    <PdfViewerEvents FormFieldUnselected="@OnFormFieldUnSelected"></PdfViewerEvents>
</SfPdfViewer2>

@code {
    private string DocumentPath = "wwwroot/data/events.pdf";

    void OnFormFieldUnSelected(FormFieldUnselectedEventArgs args)
    {
        // Access details about the unselected form field
        Console.WriteLine($"Form field unselected: {args.Field.Name}");

        // Implement additional logic, such as logging or UI updates
    }
}

FormFieldResized Event

FormFieldResized is triggered when a form field is resized. This event is useful for applying constraints on form field sizes or updating layout dynamically.

Event Arguments

The FormFieldResized event provides FormFieldResizedEventArgs, which contains Field (resized field details) and NewBounds (updated field dimensions). This event allows applying constraints on resizing.

@using Syncfusion.Blazor;
@using Syncfusion.Blazor.SfPdfViewer;

<SfPdfViewer2 Height="100%" Width="100%" DocumentPath="@DocumentPath">
    <PdfViewerEvents FormFieldResized="@OnFormFieldResized"></PdfViewerEvents>
</SfPdfViewer2>

@code {
    private string DocumentPath = "wwwroot/data/events.pdf";

    void OnFormFieldResized(FormFieldResizedEventArgs args)
    {
        // Access details about the resized form field
        Console.WriteLine($"Form field resized: {args.Field.Name}");

        // Implement additional logic, such as logging or UI updates
    }
}

ValidateFormFields Event

ValidateFormFields is triggered when form fields are validated before submission, saving, or printing the PDF. It helps ensure that required fields are filled correctly. To trigger this event, the EnableFormFieldsValidation property must be set to true in the SfPdfViewer2 component.

Event Arguments

The ValidateFormFields event provides ValidateFormFieldsArgs, which contains Fields (validated form fields). This event ensures that required fields are properly filled.

@using Syncfusion.Blazor;
@using Syncfusion.Blazor.SfPdfViewer;

<SfPdfViewer2 Height="100%" Width="100%" DocumentPath="@DocumentPath" EnableFormFieldsValidation="true">
    <PdfViewerEvents ValidateFormFields="@OnFormFieldValidated"></PdfViewerEvents>
</SfPdfViewer2>

@code {
    private string DocumentPath = "wwwroot/data/events.pdf";

    void OnFormFieldValidated(ValidateFormFieldsArgs args)
    {
        // Access details about the validated form field
        Console.WriteLine($"Form field Validated: {args.Fields[0].Name}");

        // Implement additional logic, such as logging or UI updates
    }
}

FormFieldFocusIn Event

FormFieldFocusIn is triggered when focus enters a form field while designer mode is off. It can be used to provide dynamic styling or suggestions.

Event Arguments

The FormFieldFocusIn event provides FormFieldFocusInEventArgs, which includes Field (focused form field details). It is useful for styling or displaying tooltips when a field gains focus.

@using Syncfusion.Blazor;
@using Syncfusion.Blazor.SfPdfViewer;

<SfPdfViewer2 Height="100%" Width="100%" DocumentPath="@DocumentPath" EnableFormFieldsValidation="true">
    <PdfViewerEvents FormFieldFocusIn="@OnFormFieldFocusIn"></PdfViewerEvents>
</SfPdfViewer2>

@code {
    private string DocumentPath = "wwwroot/data/events.pdf";

    void OnFormFieldFocusIn(FormFieldFocusInEventArgs args)
    {
        // Access details about the focused in form field
        Console.WriteLine($"Form field focused in: {args.Field.Name}");

        // Implement additional logic, such as logging or UI updates
    }
}

FormFieldFocusOut Event

FormFieldFocusOut is triggered when focus leaves a form field while designer mode is off. It is useful for saving data or performing validation.

Event Arguments

The FormFieldFocusOut event provides FormFieldFocusOutEventArgs, which includes Field (form field losing focus). It can be used for validation or saving data when the user moves out of a field.

@using Syncfusion.Blazor;
@using Syncfusion.Blazor.SfPdfViewer;

<SfPdfViewer2 Height="100%" Width="100%" DocumentPath="@DocumentPath" EnableFormFieldsValidation="true">
    <PdfViewerEvents FormFieldFocusOut="@OnFormFieldFocusOut"></PdfViewerEvents>
</SfPdfViewer2>

@code {
    private string DocumentPath = "wwwroot/data/events.pdf";

    void OnFormFieldFocusOut(FormFieldFocusOutEventArgs args)
    {
        // Access details about the focused out form field
        Console.WriteLine($"Form field focused out: {args.Field.Name}");

        // Implement additional logic, such as logging or UI updates
    }
}

FormFieldMouseEnter Event

FormFieldMouseEnter is triggered when the mouse enters a form field in the PDF Viewer.

Event Arguments

The FormFieldMouseEnter event provides FormFieldMouseEnterEventArgs, which includes properties like Field (form field that was entered) and PageNumber (where the field is located). This event helps implement tooltips, styling changes, or other UI enhancements when a user hovers over a field.

@using Syncfusion.Blazor;
@using Syncfusion.Blazor.SfPdfViewer;

<SfPdfViewer2 Height="100%" Width="100%" DocumentPath="@DocumentPath">
    <PdfViewerEvents FormFieldMouseEnter="@OnFormFieldMouseEnter"></PdfViewerEvents>
</SfPdfViewer2>

@code {
    private string DocumentPath = "wwwroot/data/events.pdf";

    void OnFormFieldMouseEnter(FormFieldMouseEnterEventArgs args)
    {
        // Access details about the mouse entered form field
        Console.WriteLine($"Form field Mouse entered: {args.Field.Name}");

        // Implement additional logic, such as logging or UI updates
    }
}

FormFieldMouseLeave Event

FormFieldMouseLeave is triggered when the mouse leaves a form field. It is useful for hiding tooltips or resetting styling.

Event Arguments

The FormFieldMouseLeave event provides FormFieldMouseLeaveEventArgs, which includes properties like Field (form field that was left) and PageNumber. This event is useful for reverting UI changes or hiding tooltips when the mouse leaves a field.

@using Syncfusion.Blazor;
@using Syncfusion.Blazor.SfPdfViewer;

<SfPdfViewer2 Height="100%" Width="100%" DocumentPath="@DocumentPath">
    <PdfViewerEvents FormFieldMouseLeave="@OnFormFieldMouseLeave"></PdfViewerEvents>
</SfPdfViewer2>

@code {
    private string DocumentPath = "wwwroot/data/events.pdf";

    void OnFormFieldMouseLeave(FormFieldMouseLeaveEventArgs args)
    {
        // Access details about the mouse leaved form field
        Console.WriteLine($"Form field Mouse leaved: {args.Field.Name}");

        // Implement additional logic, such as logging or UI updates
    }
}

FormFieldPropertyChanged Event

FormFieldPropertyChanged is triggered when a form field properties are modified. This event helps in tracking changes and dynamically updating UI elements.

Event Arguments

The FormFieldPropertyChanged event provides FormFieldPropertyChangedEventArgs, which contains properties like OldValue and NewValue. This event enables dynamic UI updates and validation when form field properties change.

@using Syncfusion.Blazor;
@using Syncfusion.Blazor.SfPdfViewer;

<SfPdfViewer2 Height="100%" Width="100%" DocumentPath="@DocumentPath">
    <PdfViewerEvents FormFieldPropertyChanged="@OnFormFieldPropertyChanged"></PdfViewerEvents>
</SfPdfViewer2>

@code {
    private string DocumentPath = "wwwroot/data/events.pdf";

    void OnFormFieldPropertyChanged(FormFieldPropertyChangedEventArgs args)
    {
        // Access details about the property changed form field
        Console.WriteLine($"Form field property changed: {args.NewValue}");

        // Implement additional logic, such as logging or UI updates
    }
}

IsDesignerModeChanged Event

IsDesignerModeChanged is triggered whenever the designer mode is enabled or disabled in the component. It enables developers to implement custom logic in response to the mode change, such as updating UI elements, logging events, or modifying interactions.

@using Syncfusion.Blazor;
@using Syncfusion.Blazor.SfPdfViewer;

<SfPdfViewer2 Height="100%" Width="100%" DocumentPath="@DocumentPath" IsDesignerModeChanged="IsDesignerModeChanged">
</SfPdfViewer2>

@code {
    private string DocumentPath = "wwwroot/data/events.pdf";

    void IsDesignerModeChanged(bool args)
    {
        // Check the state of Designer mode
        Console.WriteLine($"Designer mode is: {args}");

        // Implement additional logic, such as logging or UI updates
    }
}

FormFieldsExporting Event

FormFieldsExporting is triggered when the form fields export process starts in the component. It allows customization of the export process or data transformation. The export process can be canceled by setting args.Cancel = true.

Event Arguments

The FormFieldsExporting event provides FormFieldsExportEventArgs, which includes properties like Cancel. This event allows customization of the export process, such as modifying data before exporting or canceling the operation.

@using Syncfusion.Blazor;
@using Syncfusion.Blazor.Buttons;
@using Syncfusion.Blazor.SfPdfViewer;

<SfButton OnClick="ExportFields">Export Form Fields</SfButton>
<SfPdfViewer2 @ref="Viewer" Height="100%" Width="100%" DocumentPath="@DocumentPath">
    <PdfViewerEvents FormFieldsExporting="OnFormFieldsExporting"></PdfViewerEvents>
</SfPdfViewer2>

@code {
    SfPdfViewer2? Viewer;
    private string DocumentPath = "wwwroot/data/events.pdf";
    Stream JSONStream = new MemoryStream();

    void OnFormFieldsExporting(FormFieldsExportEventArgs args)
    {
        Console.WriteLine($"Form fields are being exported");

        args.Cancel = true; // Cancels the export process

        // Implement additional logic, such as logging or UI updates
    }

    private async void ExportFields()
    {
        // Export form fields as JSON Stream
        if (Viewer != null)
        {
            JSONStream = await Viewer.ExportFormFieldsAsync(FormFieldDataFormat.Json);
        }
    }
}

FormFieldsImporting Event

FormFieldsImporting is triggered when the form fields import process starts in the component. It allows validation or modification of the import process. The import operation can be canceled by setting args.Cancel = true.

Event Arguments

The FormFieldsImporting event provides FormFieldsImportEventArgs, which includes properties like Cancel. This event allows validation or modification of the form field data before importing.

@using Syncfusion.Blazor;
@using Syncfusion.Blazor.Buttons;
@using Syncfusion.Blazor.SfPdfViewer;

<SfButton OnClick="ExportFields">Export Form Fields</SfButton>
<SfButton OnClick="ImportFields">Import Form Fields</SfButton>
<SfPdfViewer2 @ref="Viewer" Height="100%" Width="100%" DocumentPath="@DocumentPath">
    <PdfViewerEvents FormFieldsImporting="OnFormFieldsImporting"></PdfViewerEvents>
</SfPdfViewer2>

@code {
    SfPdfViewer2? Viewer;
    private string DocumentPath = "wwwroot/data/events.pdf";
    Stream JSONStream = new MemoryStream();

    void OnFormFieldsImporting(FormFieldsImportEventArgs args)
    {
        Console.WriteLine($"Form fields are being imported");

        args.Cancel = true; //cancels the import process

        // Implement additional logic, such as logging or UI updates
    }

    private async void ExportFields()
    {
        // Export form fields as JSON Stream
        if (Viewer != null)
        {
            JSONStream = await Viewer.ExportFormFieldsAsync(FormFieldDataFormat.Json);
        }
    }

    private async void ImportFields()
    {
        // Import form fields as JSON Stream
        if (JSONStream != null && Viewer != null)
        {
            // Import JSON data into the viewer
            await Viewer.ImportFormFieldsAsync(JSONStream, FormFieldDataFormat.Json);
        }
    }
}

FormFieldsExported Event

FormFieldsExported is triggered when form fields are successfully exported. It allows for further processing or confirmation.

@using Syncfusion.Blazor;
@using Syncfusion.Blazor.Buttons;
@using Syncfusion.Blazor.SfPdfViewer;

<SfButton OnClick="ExportFields">Export Form Fields</SfButton>
<SfPdfViewer2 @ref="Viewer" Height="100%" Width="100%" DocumentPath="@DocumentPath">
    <PdfViewerEvents FormFieldsExported="OnFormFieldsExported"></PdfViewerEvents>
</SfPdfViewer2>

@code {
    SfPdfViewer2? Viewer;
    private string DocumentPath = "wwwroot/data/events.pdf";
    Stream JSONStream = new MemoryStream();

    void OnFormFieldsExported(FormFieldsExportedEventArgs args)
    {
        Console.WriteLine($"Form fields are exported Successfully");
        // Implement additional logic, such as logging or UI updates
    }

    private async void ExportFields()
    {
        // Export form fields as JSON Stream
        if (Viewer != null)
        {
            JSONStream = await Viewer.ExportFormFieldsAsync(FormFieldDataFormat.Json);
        }
    }
}

FormFieldsImported Event

FormFieldsImported is triggered when form fields are successfully imported into the document. This event is useful for mapping imported fields to existing data.

@using Syncfusion.Blazor;
@using Syncfusion.Blazor.Buttons;
@using Syncfusion.Blazor.SfPdfViewer;

<SfButton OnClick="ExportFields">Export Form Fields</SfButton>
<SfButton OnClick="ImportFields">Import Form Fields</SfButton>
<SfPdfViewer2 @ref="Viewer" Height="100%" Width="100%" DocumentPath="@DocumentPath">
    <PdfViewerEvents FormFieldsImported="OnFormFieldsImported"></PdfViewerEvents>
</SfPdfViewer2>
@code {
    SfPdfViewer2? Viewer;
    private string DocumentPath = "wwwroot/data/events.pdf";
    Stream JSONStream = new MemoryStream();
    void OnFormFieldsImported(FormFieldsImportedEventArgs args)
    {
        Console.WriteLine($"Form fields are imported Successfully");
        // Implement additional logic, such as logging or UI updates
    }
    private async void ExportFields()
    {
        // Export form fields as JSON Stream
        if (Viewer != null)
        {
            JSONStream = await Viewer.ExportFormFieldsAsync(FormFieldDataFormat.Json);
        }
    }
    private async void ImportFields()
    {
        // Import form fields as JSON Stream
        if (JSONStream != null && Viewer != null)
        {
            // Import JSON data into the viewer
            await Viewer.ImportFormFieldsAsync(JSONStream, FormFieldDataFormat.Json);
        }
    }
}

FormFieldsExportFailed Event

FormFieldsExportFailed is triggered when form fields export operation fails. This event can be used for error handling and debugging.

Event Arguments

The FormFieldsExportFailed event provides FormFieldsExportFailedEventArgs, which contains properties like ErrorDetails (reason for failure). It helps in handling export errors and implementing fallback mechanisms.

@using Syncfusion.Blazor;
@using Syncfusion.Blazor.Buttons;
@using Syncfusion.Blazor.SfPdfViewer;

<SfButton OnClick="ExportFields">Export Form Fields</SfButton>
<SfPdfViewer2 @ref="Viewer" Height="100%" Width="100%" DocumentPath="@DocumentPath">
    <PdfViewerEvents FormFieldsExportFailed="OnFormFieldsExportFailed"></PdfViewerEvents>
</SfPdfViewer2>

@code {
    SfPdfViewer2? Viewer;
    private string DocumentPath = "wwwroot/data/events.pdf";
    Stream JSONStream = new MemoryStream();

    void OnFormFieldsExportFailed(FormFieldsExportFailedEventArgs args)
    {
        Console.WriteLine($"Form field export is failed: {args.ErrorDetails}");
        // Implement additional logic, such as logging or UI updates
    }

    private async void ExportFields()
    {
        // Export form fields as JSON Stream
        if (Viewer != null)
        {
            JSONStream = await Viewer.ExportFormFieldsAsync(FormFieldDataFormat.Json);
        }
    }
}

FormFieldsImportFailed Event

FormFieldsImportFailed is triggered when form fields import operation fails. It helps in identifying issues and providing fallback mechanisms.

Event Arguments

The FormFieldsImportFailed event provides FormFieldsImportFailedEventArgs, which contains properties like ErrorDetails (reason for failure). This event helps in diagnosing import errors and taking corrective actions.

@using Syncfusion.Blazor;
@using Syncfusion.Blazor.Buttons;
@using Syncfusion.Blazor.SfPdfViewer;

<SfButton OnClick="ExportFields">Export Form Fields</SfButton>
<SfButton OnClick="ImportFields">Import Form Fields</SfButton>
<SfPdfViewer2 @ref="Viewer" Height="100%" Width="100%" DocumentPath="@DocumentPath">
    <PdfViewerEvents FormFieldsImportFailed="OnFormFieldsImportFailed"></PdfViewerEvents>
</SfPdfViewer2>

@code {
    SfPdfViewer2? Viewer;
    private string DocumentPath = "wwwroot/data/events.pdf";
    Stream JSONStream = new MemoryStream();

    void OnFormFieldsImportFailed(FormFieldsImportFailedEventArgs args)
    {
        Console.WriteLine($"Form field Import is failed: {args.ErrorDetails}");
        // Implement additional logic, such as logging or UI updates
    }

    private async void ExportFields()
    {
        // Export form fields as JSON Stream
        if (Viewer != null)
        {
            JSONStream = await Viewer.ExportFormFieldsAsync(FormFieldDataFormat.Json);
        }
    }

    private async void ImportFields()
    {
        // Import form fields as JSON Stream
        if (JSONStream != null && Viewer != null)
        {
            // Import JSON data into the viewer
            await Viewer.ImportFormFieldsAsync(JSONStream, FormFieldDataFormat.Json);
        }
    }
}

View sample in GitHub.

Form Designer Events in Blazor PDF Viewer

Event List

FormFieldAdding Event

Event Arguments

FormFieldAdded Event

Event Arguments

FormFieldDeleted Event

Event Arguments

FormFieldClick Event

Event Arguments

FormFieldDoubleClick Event

Event Arguments

FormFieldSelected Event

Event Arguments

FormFieldUnselected Event

Event Arguments

FormFieldResized Event

Event Arguments

ValidateFormFields Event

Event Arguments

FormFieldFocusIn Event

Event Arguments

FormFieldFocusOut Event

Event Arguments

FormFieldMouseEnter Event

Event Arguments

FormFieldMouseLeave Event

Event Arguments

FormFieldPropertyChanged Event

Event Arguments

IsDesignerModeChanged Event

FormFieldsExporting Event

Event Arguments

FormFieldsImporting Event

Event Arguments

FormFieldsExported Event

FormFieldsImported Event

FormFieldsExportFailed Event

Event Arguments

FormFieldsImportFailed Event

Event Arguments

See also