ListView.DrawSubItem 事件
定義
重要
部分資訊涉及發行前產品，在發行之前可能會有大幅修改。 Microsoft 對此處提供的資訊，不做任何明確或隱含的瑕疵擔保。
public:
event System::Windows::Forms::DrawListViewSubItemEventHandler ^ DrawSubItem;public event System.Windows.Forms.DrawListViewSubItemEventHandler DrawSubItem;public event System.Windows.Forms.DrawListViewSubItemEventHandler? DrawSubItem;member this.DrawSubItem : System.Windows.Forms.DrawListViewSubItemEventHandler Public Custom Event DrawSubItem As DrawListViewSubItemEventHandler 事件類型
範例
下列程式碼範例提供事件處理常式的實作 DrawSubItem 。 如需完整的範例，請參閱 OwnerDraw 參考主題。
// Draws subitem text and applies content-based formatting.
private void listView1_DrawSubItem(object sender,
DrawListViewSubItemEventArgs e)
{
TextFormatFlags flags = TextFormatFlags.Left;
using (StringFormat sf = new StringFormat())
{
// Store the column text alignment, letting it default
// to Left if it has not been set to Center or Right.
switch (e.Header.TextAlign)
{
case HorizontalAlignment.Center:
sf.Alignment = StringAlignment.Center;
flags = TextFormatFlags.HorizontalCenter;
break;
case HorizontalAlignment.Right:
sf.Alignment = StringAlignment.Far;
flags = TextFormatFlags.Right;
break;
}
// Draw the text and background for a subitem with a
// negative value.
double subItemValue;
if (e.ColumnIndex > 0 && Double.TryParse(
e.SubItem.Text, NumberStyles.Currency,
NumberFormatInfo.CurrentInfo, out subItemValue) &&
subItemValue < 0)
{
// Unless the item is selected, draw the standard
// background to make it stand out from the gradient.
if ((e.ItemState & ListViewItemStates.Selected) == 0)
{
e.DrawBackground();
}
// Draw the subitem text in red to highlight it.
e.Graphics.DrawString(e.SubItem.Text,
listView1.Font, Brushes.Red, e.Bounds, sf);
return;
}
// Draw normal text for a subitem with a nonnegative
// or nonnumerical value.
e.DrawText(flags);
}
}
' Draws subitem text and applies content-based formatting.
Private Sub listView1_DrawSubItem(ByVal sender As Object, _
ByVal e As DrawListViewSubItemEventArgs) _
Handles listView1.DrawSubItem
Dim flags As TextFormatFlags = TextFormatFlags.Left
Dim sf As New StringFormat()
Try
' Store the column text alignment, letting it default
' to Left if it has not been set to Center or Right.
Select Case e.Header.TextAlign
Case HorizontalAlignment.Center
sf.Alignment = StringAlignment.Center
flags = TextFormatFlags.HorizontalCenter
Case HorizontalAlignment.Right
sf.Alignment = StringAlignment.Far
flags = TextFormatFlags.Right
End Select
' Draw the text and background for a subitem with a
' negative value.
Dim subItemValue As Double
If e.ColumnIndex > 0 AndAlso _
Double.TryParse(e.SubItem.Text, NumberStyles.Currency, _
NumberFormatInfo.CurrentInfo, subItemValue) AndAlso _
subItemValue < 0 Then
' Unless the item is selected, draw the standard
' background to make it stand out from the gradient.
If (e.ItemState And ListViewItemStates.Selected) = 0 Then
e.DrawBackground()
End If
' Draw the subitem text in red to highlight it.
e.Graphics.DrawString(e.SubItem.Text, _
Me.listView1.Font, Brushes.Red, e.Bounds, sf)
Return
End If
' Draw normal text for a subitem with a nonnegative
' or nonnumerical value.
e.DrawText(flags)
Finally
sf.Dispose()
End Try
End Sub
備註
此事件可讓您使用擁有者繪圖自訂控制項的外觀 ListView 。 只有當 屬性設定為 true 且 View 屬性設定為 View.Details 時 OwnerDraw ，才會引發這個屬性。 如需擁有者繪圖的詳細資訊，請參閱 OwnerDraw 屬性參考主題。
注意
子專案資訊通常會出現在磚檢視和詳細資料檢視中，但在磚檢視中，它必須繪製在 事件的處理常式中 DrawItem 。
每個 ListView 子專案都可以發生此 DrawSubItem 事件。 您可以處理 DrawItem 事件來繪製所有子專案通用的專案，例如背景，並處理 DrawSubItem 事件來繪製個別子專案的元素，例如文字值。 您也可以只使用兩個事件之一來繪製 控制項中的所有 ListView 專案，但這可能較不方便。 若要在詳細資料檢視中繪製資料行標頭，您必須處理 DrawColumnHeader 事件。
注意
未將物件新增至 Columns 集合的任何子專案 ColumnHeader 都不會發生此 DrawSubItem 事件。 另請注意，每個 ListViewItem 物件的第一個子專案代表父專案本身，並顯示在第一個資料行中。
如需處理事件的詳細資訊，請參閱 處理和引發事件。
