DataGridViewCellFormattingEventHandler 代理人

定義

命名空間:

System.Windows.Forms

組件:

System.Windows.Forms.dll

代表將處理 CellFormatting 之 DataGridView 事件的方法。

public delegate void DataGridViewCellFormattingEventHandler(System::Object ^ sender, DataGridViewCellFormattingEventArgs ^ e);

public delegate void DataGridViewCellFormattingEventHandler(object? sender, DataGridViewCellFormattingEventArgs e);

type DataGridViewCellFormattingEventHandler = delegate of obj * DataGridViewCellFormattingEventArgs -> unit

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

參數

sender

Object

事件的來源。

e

DataGridViewCellFormattingEventArgs

DataGridViewCellFormattingEventArgs，其中包含事件資料。

範例

下列程式碼範例示範如何處理 CellFormatting 事件。

void dataGridView1_CellFormatting( Object^ /*sender*/, DataGridViewCellFormattingEventArgs^ e )
{
   // If the column is the Artist column, check the
   // value.
   if ( this->dataGridView1->Columns[ e->ColumnIndex ]->Name->Equals( "Artist" ) )
   {
      if ( e->Value != nullptr )
      {
         // Check for the string "pink" in the cell.
         String^ stringValue = dynamic_cast<String^>(e->Value);
         stringValue = stringValue->ToLower();
         if ( (stringValue->IndexOf( "pink" ) > -1) )
         {
            DataGridViewCellStyle^ pinkStyle = gcnew DataGridViewCellStyle;

            //Change the style of the cell.
            pinkStyle->BackColor = Color::Pink;
            pinkStyle->ForeColor = Color::Black;
            pinkStyle->Font = gcnew System::Drawing::Font( "Times New Roman",8,FontStyle::Bold );
            e->CellStyle = pinkStyle;
         }
         
      }
   }
   else
   if ( this->dataGridView1->Columns[ e->ColumnIndex ]->Name->Equals( "Release Date" ) )
   {
      ShortFormDateFormat( e );
   }
}


//Even though the date internaly stores the year as YYYY, using formatting, the
//UI can have the format in YY.  
void ShortFormDateFormat( DataGridViewCellFormattingEventArgs^ formatting )
{
   if ( formatting->Value != nullptr )
   {
      try
      {
         System::Text::StringBuilder^ dateString = gcnew System::Text::StringBuilder;
         DateTime theDate = 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 ( Exception^ /*notInDateFormat*/ ) 
      {
         // Set to false in case there are other handlers interested trying to
         // format this DataGridViewCellFormattingEventArgs instance.
         formatting->FormattingApplied = false;
      }

   }
}

private void dataGridView1_CellFormatting(object sender, DataGridViewCellFormattingEventArgs e)
{
    // If the column is the Artist column, check the
    // value.
    if (this.dataGridView1.Columns[e.ColumnIndex].Name == "Artist")
    {
        if (e.Value != null)
        {
            // Check for the string "pink" in the cell.
            string stringValue = (string)e.Value;
            stringValue = stringValue.ToLower();
            if ((stringValue.IndexOf("pink") > -1))
            {
                e.CellStyle.BackColor = Color.Pink;
            }
        }
    }
    else if (this.dataGridView1.Columns[e.ColumnIndex].Name == "Release Date")
    {
        ShortFormDateFormat(e);
    }
}

//Even though the date internaly stores the year as YYYY, using formatting, the
//UI can have the format in YY.  
private static void ShortFormDateFormat(DataGridViewCellFormattingEventArgs formatting)
{
    if (formatting.Value != null)
    {
        try
        {
            System.Text.StringBuilder dateString = new System.Text.StringBuilder();
            DateTime theDate = 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 (FormatException)
        {
            // Set to false in case there are other handlers interested trying to
            // format this DataGridViewCellFormattingEventArgs instance.
            formatting.FormattingApplied = false;
        }
    }
}

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

備註

CellFormatting處理 事件，根據儲存格值的狀態或值，將儲存格值轉換成適合顯示的格式，或自訂儲存格的外觀。

CellFormatting每次繪製儲存格時都會發生此事件，因此您應該避免在處理此事件時進行冗長的處理。 當擷取儲存格 FormattedValue 或其 GetFormattedValue 方法被呼叫時，也會發生這個事件。

當您處理事件時 CellFormatting ， ConvertEventArgs.Value 屬性會以資料格值初始化。 如果您提供從儲存格值到顯示值的自訂轉換，請將 ConvertEventArgs.Value 屬性設定為已轉換的值，確保新值是儲存格 FormattedValueType 屬性所指定的類型。 若要指出不需要進一步的值格式設定，請將 DataGridViewCellFormattingEventArgs.FormattingApplied 屬性設定為 true 。

當事件處理常式完成時，如果 ConvertEventArgs.Value 為 null 或 不是正確的型別，或 DataGridViewCellFormattingEventArgs.FormattingApplied 屬性為 false ，則會 Value 使用 Format 屬性所 DataGridViewCellFormattingEventArgs.CellStyle 傳回之儲存格樣式的 、 DataSourceNullValueNullValue 、 和 FormatProvider 屬性來格式化，而此屬性會使用儲存格 InheritedStyle 屬性初始化。

不論 屬性的值 DataGridViewCellFormattingEventArgs.FormattingApplied 為何，屬性所 DataGridViewCellFormattingEventArgs.CellStyle 傳回物件的顯示內容都會用來呈現儲存格。

如需使用 CellFormatting 事件自訂格式的詳細資訊，請參閱How to： Customize Data Formatting in the Windows Forms DataGridView Control。

若要避免處理此事件時的效能損失，請透過事件處理常式的參數存取資料格，而不是直接存取資料格。

若要自訂格式化的使用者指定值轉換成實際儲存格值，請處理 CellParsing 事件。

如需如何處理事件的詳細資訊，請參閱 處理和引發事件。

建立 DataGridViewCellFormattingEventHandler 委派時，必須識別處理事件的方法。 若要使事件與您的事件處理常式產生關聯，請將委派的執行個體 (Instance) 加入至事件。 除非您移除委派，否則每當事件發生時就會呼叫事件處理常式。 如需事件處理常式委派的詳細資訊，請參閱 處理和引發事件。

擴充方法

另請參閱

• DataGridView
• CellFormatting
• DataGridViewCellFormattingEventArgs
• DataGridViewCellStyle
• Windows Form DataGridView 控制項中的儲存格樣式
• 操作說明：自訂 Windows Forms DataGridView 控制項中的資料格式