DataGridViewCellFormattingEventHandler Delegate


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

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

Public Delegate Sub DataGridViewCellFormattingEventHandler (
	sender As Object,
	e As DataGridViewCellFormattingEventArgs


Type: System.Object

The source of the event.

Type: System.Windows.Forms.DataGridViewCellFormattingEventArgs

A DataGridViewCellFormattingEventArgs that contains the event data.

Handle the CellFormatting event to customize the conversion of a cell value into a format suitable for display or to customize the appearance of a cell depending on its state or value.

The CellFormatting event occurs every time each cell is painted, so you should avoid lengthy processing when handling this event. This event also occurs when the cell FormattedValue is retrieved or its GetFormattedValue method is called.

When you handle the CellFormatting event, the ConvertEventArgs.Value property is initialized with the cell value. If you provide custom conversion from the cell value to the display value, set the ConvertEventArgs.Value property to the converted value, ensuring that the new value is of the type specified by the cell FormattedValueType property. To indicate that no further value formatting is necessary, set the DataGridViewCellFormattingEventArgs.FormattingApplied property to true.

When the event handler completes, if the ConvertEventArgs.Value is null or is not of the correct type, or the DataGridViewCellFormattingEventArgs.FormattingApplied property is false, the Value is formatted using the Format, NullValue, DataSourceNullValue, and FormatProvider properties of the cell style returned by the DataGridViewCellFormattingEventArgs.CellStyle property, which is initialized using the cell InheritedStyle property.

Regardless of the value of the DataGridViewCellFormattingEventArgs.FormattingApplied property, the display properties of the object returned by the DataGridViewCellFormattingEventArgs.CellStyle property are used to render the cell.

For more information about custom formatting using the CellFormatting event, see How to: Customize Data Formatting in the Windows Forms DataGridView Control.

To avoid performance penalties when handling this event, access the cell through the parameters of the event handler rather than accessing the cell directly.

To customize the conversion of a formatted, user-specified value into an actual cell value, handle the CellParsing event.

For more information about handling events, see NIB: Consuming Events.

When you create a DataGridViewCellFormattingEventHandler 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 NIB: Events and Delegates.

The following code example demonstrates how to handle the CellFormatting event.

Private Sub dataGridView1_CellFormatting(ByVal sender As Object, _
    ByVal e As DataGridViewCellFormattingEventArgs) _
    Handles dataGridView1.CellFormatting
    ' If the column is the Artist column, check the
    ' value.
    If Me.dataGridView1.Columns(e.ColumnIndex).Name _
        = "Artist" Then
        If e.Value IsNot Nothing Then

            ' Check for the string "pink" in the cell.
            Dim stringValue As String = _
            CType(e.Value, String)
            stringValue = stringValue.ToLower()
            If ((stringValue.IndexOf("pink") > -1)) Then
                e.CellStyle.BackColor = Color.Pink
            End If

        End If
    ElseIf Me.dataGridView1.Columns(e.ColumnIndex).Name _
        = "Release Date" Then
    End If
End Sub

'Even though the date internaly stores the year as YYYY, using formatting, the
'UI can have the format in YY.  
Private Shared Sub ShortFormDateFormat(ByVal formatting As DataGridViewCellFormattingEventArgs)
    If formatting.Value IsNot Nothing Then
            Dim dateString As System.Text.StringBuilder = New System.Text.StringBuilder()
            Dim theDate As Date = DateTime.Parse(formatting.Value.ToString())

            formatting.Value = dateString.ToString()
            formatting.FormattingApplied = True
        Catch notInDateFormat As FormatException
            ' Set to false in case there are other handlers interested trying to
            ' format this DataGridViewCellFormattingEventArgs instance.
            formatting.FormattingApplied = False
        End Try
    End If
End Sub

.NET Framework
Available since 2.0
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