Prevent default Tree Grid action in Blazor TreeGrid Component

13 Sep 20216 minutes to read

The default Tree Grid actions can be prevented by canceling them in the OnActionBegin event.

This is demonstrated in the below sample code where the Add operation is prevented by setting Cancel argument value of the OnActionBegin event to false.

RAZOR

@using TreeGridComponent.Data;
@using  Syncfusion.Blazor.Grids;
@using  Syncfusion.Blazor.TreeGrid;

<SfTreeGrid @ref="TreeGrid" DataSource="@TreeGridData" IdMapping="TaskId" ParentIdMapping="ParentId"
            TreeColumnIndex="1" AllowPaging="true" Toolbar="@(new List<string>() { "Add", "Delete", "Edit","Update", "Cancel" })">
    <TreeGridEvents OnActionBegin="OnActionBegin" TValue="TreeData"></TreeGridEvents>
    <TreeGridEditSettings AllowAdding="true" AllowEditing="true" AllowDeleting="true"></TreeGridEditSettings>
    <TreeGridPageSettings PageSize="8"></TreeGridPageSettings>
    <TreeGridColumns>
        <TreeGridColumn Field="TaskId" HeaderText="Task ID" IsPrimaryKey="true" Width="80" TextAlign="Syncfusion.Blazor.Grids.TextAlign.Right"></TreeGridColumn>
        <TreeGridColumn Field="TaskName" HeaderText="Task Name" Width="160">
        </TreeGridColumn>
        <TreeGridColumn Field="Priority" HeaderText="Priority" Width="80">
        </TreeGridColumn>
        <TreeGridColumn Field="Duration" HeaderText="Duration" Width="100" TextAlign="Syncfusion.Blazor.Grids.TextAlign.Right">
        </TreeGridColumn>
        <TreeGridColumn Field="Progress" HeaderText="Progress" Width="100" TextAlign="Syncfusion.Blazor.Grids.TextAlign.Right"></TreeGridColumn>
    </TreeGridColumns>
</SfTreeGrid>

@code{
    SfTreeGrid<TreeData> TreeGrid;

    public List<TreeData> TreeGridData { get; set; }

    protected override void OnInitialized()
    {
        this.TreeGridData = TreeData.GetSelfDataSource().ToList();
    }
    public void OnActionBegin(ActionEventArgs<TreeData> args)
    {
        if (args.RequestType == Syncfusion.Blazor.Grids.Action.Add)
        {
            args.Cancel = true;
        }
    }
}

C#

namespace TreeGridComponent.Data {

public class TreeData
    {
        public int TaskId { get; set; }
        public string TaskName { get; set; }
        public int? Duration { get; set; }
        public int? Progress { get; set; }
        public string Priority { get; set; }
        public int? ParentId { get; set; }

        public static List<TreeData> GetSelfDataSource()
        {
            List<TreeData> TreeDataCollection = new List<TreeData>();
            TreeDataCollection.Add(new TreeData() { TaskId = 1, TaskName = "Parent Task 1", Duration = 10, Progress = 70, Priority = "Critical", ParentId = null });
            TreeDataCollection.Add(new TreeData() { TaskId = 2, TaskName = "Child task 1", Progress = 80, Priority = "Low", Duration = 50, ParentId = 1 });
            TreeDataCollection.Add(new TreeData() { TaskId = 3, TaskName = "Child Task 2", Duration = 5, Progress = 65, Priority = "Critical", ParentId = 2 });
            TreeDataCollection.Add(new TreeData() { TaskId = 4, TaskName = "Child task 3", Duration = 6, Priority = "High", Progress = 77, ParentId = 3 });
            TreeDataCollection.Add(new TreeData() { TaskId = 5, TaskName = "Parent Task 2", Duration = 10, Progress = 70, Priority = "Critical", ParentId = null });
            TreeDataCollection.Add(new TreeData() { TaskId = 6, TaskName = "Child task 1", Duration = 4, Progress = 80, Priority = "Critical", ParentId = 5 });
            TreeDataCollection.Add(new TreeData() { TaskId = 7, TaskName = "Child Task 2", Duration = 5, Progress = 65, Priority = "Low", ParentId = 5 });
            TreeDataCollection.Add(new TreeData() { TaskId = 8, TaskName = "Child task 3", Duration = 6, Progress = 77, Priority = "High", ParentId = 5 });
            TreeDataCollection.Add(new TreeData() { TaskId = 9, TaskName = "Child task 4", Duration = 6, Progress = 77, Priority = "Low", ParentId = 5 });
            return TreeDataCollection;
        }
    }
}