DataGridViewRowContextMenuStripNeededEventHandler Delegate

Definition

Namespace:

System.Windows.Forms

Assembly:

System.Windows.Forms.dll

Source:

DataGridViewEventHandlers.cs

Represents the method that will handle the RowContextMenuStripNeeded event of a DataGridView.

public delegate void DataGridViewRowContextMenuStripNeededEventHandler(System::Object ^ sender, DataGridViewRowContextMenuStripNeededEventArgs ^ e);

public delegate void DataGridViewRowContextMenuStripNeededEventHandler(object? sender, DataGridViewRowContextMenuStripNeededEventArgs e);

type DataGridViewRowContextMenuStripNeededEventHandler = delegate of obj * DataGridViewRowContextMenuStripNeededEventArgs -> unit

Public Delegate Sub DataGridViewRowContextMenuStripNeededEventHandler(sender As Object, e As DataGridViewRowContextMenuStripNeededEventArgs)

Parameters

sender

Object

The source of the event.

e

DataGridViewRowContextMenuStripNeededEventArgs

A DataGridViewRowContextMenuStripNeededEventArgs that contains the event data.

Examples

In the following code example, the RowContextMenuStripNeeded event is handled to provide a ContextMenuStrip based on the title of the employee. In this example, two there are two context menus, one for managers and one for all other employees.

void dataGridView1_RowContextMenuStripNeeded(object sender,
    DataGridViewRowContextMenuStripNeededEventArgs e)
{
    DataGridViewRow dataGridViewRow1 = dataGridView1.Rows[e.RowIndex];

    toolStripMenuItem1.Enabled = true;

    // Show the appropriate ContextMenuStrip based on the employees title.
    if ((dataGridViewRow1.Cells["Title"].Value.ToString() ==
        "Sales Manager") ||
        (dataGridViewRow1.Cells["Title"].Value.ToString() ==
        "Vice President, Sales"))
    {
        e.ContextMenuStrip = managerMenuStrip;
    }
    else
    {
        e.ContextMenuStrip = employeeMenuStrip;
    }

    contextMenuRowIndex = e.RowIndex;
}

Public Sub dataGridView1_RowContextMenuStripNeeded( _
    ByVal sender As Object, _
    ByVal e As DataGridViewRowContextMenuStripNeededEventArgs) _
    Handles dataGridView1.RowContextMenuStripNeeded

    Dim dataGridViewRow1 As DataGridViewRow = _
    dataGridView1.Rows(e.RowIndex)

    toolStripMenuItem1.Enabled = True

    ' Show the appropriate ContextMenuStrip based on the employees title.
    If dataGridViewRow1.Cells("Title").Value.ToString() = _
        "Sales Manager" OrElse _
        dataGridViewRow1.Cells("Title").Value.ToString() = _
        "Vice President, Sales" Then

        e.ContextMenuStrip = managerMenuStrip
    Else
        e.ContextMenuStrip = employeeMenuStrip
    End If

    contextMenuRowIndex = e.RowIndex
End Sub

Remarks

The RowContextMenuStripNeeded event occurs only when the DataGridView control DataSource property is set or its VirtualMode property is true. Handling the RowContextMenuStripNeeded event is useful when you want to display a shortcut menu determined by a row's current state or the values it contains.

When you handle the RowContextMenuStripNeeded event, the shortcut menu that you specify in the handler is shown whenever the user right-clicks a row unless the CellContextMenuStripNeeded overrides the shortcut menu for the specific cell that was clicked.

The RowContextMenuStripNeeded event also occurs whenever the value of the DataGridViewRow.ContextMenuStrip property is retrieved, either programmatically or when the user right-clicks a row.

You can use the DataGridViewRowContextMenuStripNeededEventArgs.RowIndex property to determine the state of a row or the values it contains, and use this information to change or modify the DataGridViewRowContextMenuStripNeededEventArgs.ContextMenuStrip property. This property is initialized with the value of the row ContextMenuStrip property, which the event value overrides.

Handle the RowContextMenuStripNeeded event when working with large amounts of data to avoid the performance penalties of setting the row ContextMenuStrip value for multiple rows. For more information, see Best Practices for Scaling the Windows Forms DataGridView Control.

For more information about how to handle events, see Handling and Raising Events.

When you create a DataGridViewRowContextMenuStripNeededEventHandler delegate, you identify the method that will handle the event. To associate the event with your event handler, add an instance of the delegate to the event. The event handler is called whenever the event occurs, unless you remove the delegate. For more information about event-handler delegates, see Handling and Raising Events.

Extension Methods

See also

• ContextMenuStrip
• DataGridView
• RowContextMenuStripNeeded
• DataSource
• VirtualMode
• DataGridViewRowContextMenuStripNeededEventArgs
• ContextMenuStrip
• ContextMenuStrip
• Best Practices for Scaling the Windows Forms DataGridView Control