Getting Started with Blazor Dialog in Blazor Server App

28 Aug 20269 minutes to read

This section briefly explains how to include the Blazor Dialog component in a Blazor Server App using Visual Studio, Visual Studio Code, and the .NET CLI.

Create a new Blazor Server App

• Visual Studio
• Visual Studio Code
• .NET CLI

Create a Blazor Server App by using the Blazor Web App template in Visual Studio via Microsoft Templates or the Syncfusion® Blazor Extension.

Run the following command to create a new Blazor Server App.

Terminal

dotnet new blazor -o BlazorApp --interactivity Server
cd BlazorApp

Alternatively, create a Blazor Server App using Visual Studio Code via Microsoft Templates or the Syncfusion® Blazor Extension, or the C# Dev Kit extension.

Run the following command to create a new Blazor Server App.

Command Prompt

dotnet new blazor -o BlazorApp --interactivity Server
cd BlazorApp

Configure the appropriate Interactive render mode and Interactivity location while creating a Blazor Server App. For detailed information, refer to the interactive render mode documentation.

Install the required Blazor packages

Install the Syncfusion.Blazor.Popups and Syncfusion.Blazor.Themes NuGet packages. All Syncfusion Blazor packages are available on nuget.org. See the NuGet packages topic for details.

• Visual Studio
• Visual Studio Code
• .NET CLI

1. Go to Tools → NuGet Package Manager → Manage NuGet Packages for Solution.
2. Search the required NuGet packages (Syncfusion.Blazor.Popups and Syncfusion.Blazor.Themes) and install them.

Alternatively, you can install the same packages using the Package Manager Console with the following commands.

Package Manager Console

Install-Package Syncfusion.Blazor.Popups -Version 35.1.37
Install-Package Syncfusion.Blazor.Themes -Version 35.1.37

Open the terminal and run the following commands.

Terminal

dotnet add package Syncfusion.Blazor.Popups -v 35.1.37
dotnet add package Syncfusion.Blazor.Themes -v 35.1.37

Open the command prompt and run the following commands.

Command Prompt

dotnet add package Syncfusion.Blazor.Popups -v 35.1.37
dotnet add package Syncfusion.Blazor.Themes -v 35.1.37

Add import namespaces

After the packages are installed, open the ~/_Imports.razor file and import the Syncfusion.Blazor and Syncfusion.Blazor.Popups namespaces.

~/_Imports.razor

@using Syncfusion.Blazor
@using Syncfusion.Blazor.Popups

Register the Blazor service

Open the Program.cs file in Blazor Server App and register the Blazor service and include the required namespace reference using Syncfusion.Blazor; at the top.

Program.cs

builder.Services.AddSyncfusionBlazor();

Add stylesheet and script resources

The theme stylesheet and script can be accessed from NuGet through Static Web Assets. Include the stylesheet at the end of the <head> section in the App.razor file.

App.razor

<link href="_content/Syncfusion.Blazor.Themes/fluent2.css" rel="stylesheet" />

Include the required script references at the end of the <body> section in the App.razor file to enable Dialog functionality.

App.razor

<script src="_content/Syncfusion.Blazor.Core/scripts/syncfusion-blazor.min.js" type="text/javascript"></script>

Add Blazor Dialog component

Open a Razor file located in the ~/Pages/*.razor (for example, Home.razor) and add the Blazor Dialog component inside the Razor file.

If the interactivity location is set to Per page/component, define a render mode at the top of the Razor file (For example, InteractiveServer). If the Interactivity is set to Global, the render mode is automatically configured in the App.razor file by default.

Home.razor

@rendermode InteractiveServer

<SfDialog Width="250px">
    <DialogTemplates>
        <Content> This is a Dialog with content </Content>
    </DialogTemplates>
</SfDialog>

Run the application

• Visual Studio
• Visual Studio Code
• .NET CLI

Press Ctrl+F5 (Windows) or ⌘+F5 (macOS) to launch the application. The Blazor Dialog component will render in your default web browser.

Open the terminal and run the following command.

Terminal

dotnet run

Open the command prompt and run the following command.

Command Prompt

dotnet run

• In the dialog control, max-height is calculated based on the dialog target element height. If the Target property is not configured, the document.body is considered as a target. Therefore, to show a dialog in proper height, you need to add min-height to the target element.

• If the dialog is rendered based on the body, then the dialog will get the height based on its body element height. If the height of the dialog is larger than the body height, then the dialog’s height will not be set. For this scenario, you can set the CSS style for the html and body to get the dialog height.

app.css

html, body {
   height: 100%;
}

Created and Destroyed Events

• The Created event fires when the dialog is initialized and rendered in the DOM.

• The Destroyed event triggers when the Blazor Dialog component is removed from the DOM. These lifecycle events allow executing custom code at specific points in the component’s existence.

Home.razor

<SfDialog>
    <DialogEvents Created="@CreatedHandler" Destroyed="@DestroyedHandler"></DialogEvents>
</SfDialog>
@code
{
    public void CreatedHandler(Object args)
    {
        // Here, you can customize your code.
    }

    private void DestroyedHandler()
    {
        // Here, you can customize your code.
    }
}

Prerender the Dialog

The AllowPrerender property controls how the dialog DOM elements are handled when the dialog is hidden. Understanding this property is crucial for optimizing performance in your application.

• By default, AllowPrerender is set to false. In this mode, dialog DOM elements are completely removed from the DOM when the dialog is hidden, and recreated each time the dialog is shown. This approach saves memory but requires re-rendering on each display.
• When AllowPrerender is set to true, the dialog elements remain in the DOM even when hidden, which improves performance for frequently accessed dialogs but uses more memory.

Home.razor

@using Syncfusion.Blazor.Buttons

<div id="target">
    <div>
        <button class="e-btn" @onclick="@OnBtnClick">Open</button>
    </div>
    <SfDialog Target="#target" Width="300px" ShowCloseIcon="true" @bind-Visible="Visibility" AllowPrerender="true" Header="AllowPrerender Dialog" Content="This is a dialog with content">
    </SfDialog>
</div>
<style>
    #target {
        height: 500px;
    }
</style>
@code 
{
    private bool Visibility { get; set; } = false;
    private void OnBtnClick()
    {
        this.Visibility = true;
    }
}

Set Header to Dialog

The Header property allows rendering a dialog with a custom text header.

Home.razor

<SfDialog Width="250px" Header="Dialog Header"></SfDialog>

Set Content to Dialog

The Content property allows rendering a dialog with a custom text content.

Home.razor

<SfDialog Width="250px" Content="This is a dialog with Content property."></SfDialog>

View Sample in GitHub.

See also

1. Getting Started with Blazor Web App
2. Getting Started with Blazor WebAssembly App
3. Getting Started with Blazor Dialog Template