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DataGridView.CellFormatting Event

Note: This event is new in the .NET Framework version 2.0.

Occurs when the contents of a cell need to be formatted for display.

Namespace: System.Windows.Forms
Assembly: System.Windows.Forms (in system.windows.forms.dll)

'Declaration
Public Event CellFormatting As DataGridViewCellFormattingEventHandler
'Usage
Dim instance As DataGridView
Dim handler As DataGridViewCellFormattingEventHandler

AddHandler instance.CellFormatting, handler

/** @event */
public void add_CellFormatting (DataGridViewCellFormattingEventHandler value)

/** @event */
public void remove_CellFormatting (DataGridViewCellFormattingEventHandler value)

JScript supports the use of events, but not the declaration of new ones.

By default, the DataGridView control will attempt to convert a cell's value into a format suitable for display. For example, it will convert a numerical value into a string for display in a text box cell. You can indicate the formatting convention to use by setting the Format property of the DataGridViewCellStyle returned by properties such as the DefaultCellStyle property.

If the standard formatting is insufficient, you can customize the formatting by handling the CellFormatting event. This event lets you indicate the exact display value as well as the cell styles, such as background and foreground color, to use for the cell display. This means you can handle this event for any kind of cell formatting, regardless of whether the cell value itself needs formatting.

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 a null reference (Nothing in Visual Basic) 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 Consuming Events.

The following code example shows 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
        ShortFormDateFormat(e)
    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
        Try
            Dim dateString As System.Text.StringBuilder = New System.Text.StringBuilder()
            Dim theDate As Date = DateTime.Parse(formatting.Value.ToString())

            dateString.Append(theDate.Month)
            dateString.Append("/")
            dateString.Append(theDate.Day)
            dateString.Append("/")
            dateString.Append(theDate.Year.ToString().Substring(2))
            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

Windows 98, Windows 2000 SP4, Windows Millennium Edition, Windows Server 2003, Windows XP Media Center Edition, Windows XP Professional x64 Edition, Windows XP SP2, Windows XP Starter Edition

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

.NET Framework

Supported in: 2.0

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