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DataGridViewCellContextMenuStripNeededEventArgs Class

Provides data for the CellContextMenuStripNeeded event.

System.Object
  System.EventArgs
    System.Windows.Forms.DataGridViewCellEventArgs
      System.Windows.Forms.DataGridViewCellContextMenuStripNeededEventArgs

Namespace:  System.Windows.Forms
Assembly:  System.Windows.Forms (in System.Windows.Forms.dll)

'Declaration
Public Class DataGridViewCellContextMenuStripNeededEventArgs _
	Inherits DataGridViewCellEventArgs

The DataGridViewCellContextMenuStripNeededEventArgs type exposes the following members.

  NameDescription
Public methodDataGridViewCellContextMenuStripNeededEventArgsInitializes a new instance of the DataGridViewCellContextMenuStripNeededEventArgs class.
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  NameDescription
Public propertyColumnIndexGets a value indicating the column index of the cell that the event occurs for. (Inherited from DataGridViewCellEventArgs.)
Public propertyContextMenuStripGets or sets the shortcut menu for the cell that raised the CellContextMenuStripNeeded event.
Public propertyRowIndexGets a value indicating the row index of the cell that the event occurs for. (Inherited from DataGridViewCellEventArgs.)
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  NameDescription
Public methodEquals(Object)Determines whether the specified object is equal to the current object. (Inherited from Object.)
Protected methodFinalizeAllows an object to try to free resources and perform other cleanup operations before it is reclaimed by garbage collection. (Inherited from Object.)
Public methodGetHashCodeServes as the default hash function. (Inherited from Object.)
Public methodGetTypeGets the Type of the current instance. (Inherited from Object.)
Protected methodMemberwiseCloneCreates a shallow copy of the current Object. (Inherited from Object.)
Public methodToStringReturns a string that represents the current object. (Inherited from Object.)
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The CellContextMenuStripNeeded event occurs only when the DataGridView control DataSource property is set or its VirtualMode property is true.

When you handle the CellContextMenuStripNeeded event, the shortcut menu that you specify in the handler is shown whenever the user right-clicks a cell. This is useful when you want to display shortcut menus determined by the current state or value of a cell.

The CellContextMenuStripNeeded event also occurs whenever the value of the DataGridViewCell.ContextMenuStrip property is retrieved, either programmatically or when the user right-clicks the cell.

You can use the ColumnIndex and RowIndex properties to determine the state or value of a cell, and use this information to set the ContextMenuStrip property. This property is initialized with the value of the cell ContextMenuStrip property, which the event value overrides.

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

You can also specify shortcut menus for individual rows rather than individual cells by setting the row ContextMenuStrip property or handling the DataGridView control's RowContextMenuStripNeeded event. The cell ContextMenuStrip property setting overrides the row ContextMenuStrip property setting, and the CellContextMenuStripNeeded event overrides both the RowContextMenuStripNeeded event and the row ContextMenuStrip property setting. You can specify Nothing for a cell shortcut menu, however, to prevent a row shortcut menu from being overridden.

For more information about handling events, see Consuming Events.

The following code example uses the DataGridViewCellContextMenuStripNeededEventArgs class to set the shortcut menu without unsharing the row.

Private WithEvents wholeTable As New ToolStripMenuItem()
Private WithEvents lookUp As New ToolStripMenuItem()
Private strip As ContextMenuStrip
Private cellErrorText As String 

Private Sub dataGridView1_CellContextMenuStripNeeded(ByVal sender As Object, _
    ByVal e As DataGridViewCellContextMenuStripNeededEventArgs) _
    Handles dataGridView1.CellContextMenuStripNeeded

    cellErrorText = String.Empty

    If strip Is Nothing Then
        strip = New ContextMenuStrip()
        lookUp.Text = "Look Up"
        wholeTable.Text = "See Whole Table"
        strip.Items.Add(lookUp)
        strip.Items.Add(wholeTable)
    End If
    e.ContextMenuStrip = strip
End Sub 

Private Sub wholeTable_Click(ByVal sender As Object, ByVal e As EventArgs) Handles wholeTable.Click
    dataGridView1.DataSource = Populate("Select * from employees", True)
End Sub 

Private theCellImHoveringOver As DataGridViewCellEventArgs

Private Sub dataGridView1_CellMouseEnter(ByVal sender As Object, _
    ByVal e As DataGridViewCellEventArgs) _
    Handles dataGridView1.CellMouseEnter

    theCellImHoveringOver = e
End Sub 

Private cellErrorLocation As DataGridViewCellEventArgs

Private Sub lookUp_Click(ByVal sender As Object, ByVal e As EventArgs) Handles lookUp.Click
    Try
        dataGridView1.DataSource = Populate("Select * from employees where " & _
            dataGridView1.Columns(theCellImHoveringOver.ColumnIndex).Name & " = '" & _
            dataGridView1.Rows(theCellImHoveringOver.RowIndex).Cells(theCellImHoveringOver.ColumnIndex).Value.ToString() & _
            "'", True)
    Catch ex As SqlException
        cellErrorText = "Can't look this cell up"
        cellErrorLocation = theCellImHoveringOver
    End Try 
End Sub 

Private Sub dataGridView1_CellErrorTextNeeded(ByVal sender As Object, _
            ByVal e As DataGridViewCellErrorTextNeededEventArgs) _
            Handles dataGridView1.CellErrorTextNeeded
    If (Not cellErrorLocation Is Nothing) Then 
        If e.ColumnIndex = cellErrorLocation.ColumnIndex AndAlso _
            e.RowIndex = cellErrorLocation.RowIndex Then
            e.ErrorText = cellErrorText
        End If 
    End If 
End Sub 

Private Function Populate(ByVal query As String, ByVal resetUnsharedCounter As Boolean) As DataTable

    If resetUnsharedCounter Then
        ResetCounter()
    End If 

    ' Alter the data source as necessary 
    Dim adapter As New SqlDataAdapter(query, _
        New SqlConnection("Integrated Security=SSPI;Persist Security Info=False;" & _
        "Initial Catalog=Northwind;Data Source=localhost"))

    Dim table As New DataTable()
    table.Locale = System.Globalization.CultureInfo.InvariantCulture
    adapter.Fill(table)
    Return table
End Function 

Private count As New Label()
Private unsharedRowCounter As Integer 

Private Sub ResetCounter()
    unsharedRowCounter = 0
    count.Text = unsharedRowCounter.ToString()
End Sub

.NET Framework

Supported in: 4.5.2, 4.5.1, 4.5, 4, 3.5, 3.0, 2.0

.NET Framework Client Profile

Supported in: 4, 3.5 SP1

Windows 8.1, Windows Server 2012 R2, Windows 8, Windows Server 2012, Windows 7, Windows Vista SP2, Windows Server 2008 (Server Core Role not supported), Windows Server 2008 R2 (Server Core Role supported with SP1 or later; Itanium not supported)

The .NET Framework does not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.

Any public static (Shared in Visual Basic) members of this type are thread safe. Any instance members are not guaranteed to be thread safe.
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