In this article I will explain with an example, how to delete a row from temporary DataTable bound to GridView in ASP.Net.
 
 

HTML Markup

The HTML Markup consists of:
GridView - For displaying data.

Columns

The GridView consists of two BoundField columns and a CommandField column.
<asp:GridView ID="gvCustomers" CssClass="Grid" runat="server" OnRowDeleting="OnRowDeleting" AutoGenerateColumns="false" OnRowDataBound="OnRowDataBound">
    <Columns>
        <asp:BoundField DataField="Item" HeaderText="Item" />
        <asp:BoundField DataField="Price" HeaderText="Price" />
        <asp:CommandField ShowDeleteButton="True" ButtonType="Button" />
    </Columns>
</asp:GridView>`
 
 

Binding the GridView

Inside the Page_Load event handler, an object of DataTable is created.
Then, two columns are added to the DataTable Columns collection using the AddRange method.
Once the schema is ready i.e. all the columns are defined, some rows have been added using the Rows.Add method.
Finally, the DataTable value is saved in ViewState variable.
C#
protected void Page_Load(object sender, EventArgs e)
{
    if (!Page.IsPostBack)
    {
        DataTable dt = new DataTable();
        dt.Columns.AddRange(new DataColumn[2] {
                            new DataColumn("Item"),
                            new DataColumn("Price") });
        dt.Rows.Add("Shirt", 450);
        dt.Rows.Add("Jeans", 3200);
        dt.Rows.Add("Trousers", 1900);
        dt.Rows.Add("Tie", 185);
        dt.Rows.Add("Cap", 100);
        dt.Rows.Add("Hat", 120);
        dt.Rows.Add("Scarf", 290);
        dt.Rows.Add("Belt", 150);
        ViewState["dt"] = dt;
        BindGrid();
    }
}
protected void BindGrid()
{
    gvCustomers.DataSource = ViewState["dt"] as DataTable;
    gvCustomers.DataBind();
} 
 
VB.Net
Protected Sub  Page_Load(sender As Object, e As EventArgs) Handles Me.Load
    If Not Page.IsPostBackThen
        Dim dt As New DataTable()
        dt.Columns.AddRange(New DataColumn(1) {
                            New DataColumn("Item"),
                            New DataColumn("Price")})
        dt.Rows.Add("Shirt", 450)
        dt.Rows.Add("Jeans", 3200)
        dt.Rows.Add("Trousers", 1900)
        dt.Rows.Add("Tie", 185)
        dt.Rows.Add("Cap", 100)
        dt.Rows.Add("Hat", 120)
        dt.Rows.Add("Scarf", 290)
        dt.Rows.Add("Belt", 150)
        ViewState("dt") = dt
        BindGrid()
    End If
End Sub
Protected Sub BindGrid()
    gvCustomers.DataSource = TryCast(ViewState("dt"), DataTable)
    gvCustomers.DataBind()
End Sub
 
 

Applying the JavaScript Confirmation Box to the GridView CommandField Delete Button

Inside the OnRowDataBound event handler, a loop is executed over the Button controls of the GridView Cell. If the CommandName of the Button is Delete, then JavaScript Confirmation Box script is assigned to its OnClick attribute.
C#
protected void OnRowDataBound(object sender, GridViewRowEventArgs e)
{
    if  (e.Row.RowType == DataControlRowType.DataRow)
    {
        string item = e.Row.Cells[0].Text;
        foreach (Button button in e.Row.Cells[2].Controls.OfType<Button>())
        {
            if  (button.CommandName == "Delete")
            {
                button.Attributes["onclick"] = "if(!confirm('Do you want to delete " + item + "?')){ return false; };";
            }
        }
    }
}
 
VB.Net
Protected Sub OnRowDataBound(sender As Object, e As GridViewRowEventArgs)
    If e.Row.RowType = DataControlRowType.DataRow Then
        Dim item As String = e.Row.Cells(0).Text
        For Each button As Button In e.Row.Cells(2).Controls.OfType(Of Button)()
            If button.CommandName = "Delete" Then
                button.Attributes("onclick") = "if(!confirm('Do you want to delete " + item + "?')){ return false; };"
            End If
        Next
    End If
End Sub
 
 

Delete the ASP.Net GridView Row using CommandField and OnRowDeleting event

When the Delete Button is clicked, the OnRowDeleting event handler is executed. Inside the OnRowDeleting event handler, the Index of the GridView Row is determined and it is used to delete the Row from the DataTable.Finally the DataTable is saved back to the ViewState and the GridView is again populated.
C#
protected void OnRowDeleting(object sender, GridViewDeleteEventArgs e)
{
    int index = Convert.ToInt32(e.RowIndex);
    DataTable dt = ViewState["dt"]as DataTable;
    dt.Rows[index].Delete();
    ViewState["dt"] = dt;
    BindGrid();
} 
 
VB.Net
Protected Sub OnRowDeleting(sender As Object, e As GridViewDeleteEventArgs)
    Dim index As Integer = Convert.ToInt32(e.RowIndex)
    Dim dt As DataTable = TryCast(ViewState("dt"), DataTable)
    dt.Rows(index).Delete()
    ViewState("dt") = dt
    BindGrid()
End Sub
 
 

Screenshot

ASP.Net: Delete a Row from Temporary DataTable bound to GridView  
 

Demo

View Demo
 
 

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