ListBox.HorizontalExtent 属性   
定义
重要
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获取或设置 ListBox 的水平滚动条可滚动的宽度。
public:
 property int HorizontalExtent { int get(); void set(int value); };public int HorizontalExtent { get; set; }member this.HorizontalExtent : int with get, setPublic Property HorizontalExtent As Integer属性值
水平滚动条可滚动控件的宽度,以像素为单位。 默认值为零。
示例
下面的代码示例演示如何使用 HorizontalScrollbar 和 HorizontalExtent 属性显示显示控件中 ListBox 所有项文本的水平滚动条。 该示例还使用 IntegralHeight 该属性来确保由于控件的大小 ListBox 而未部分显示项。 此示例要求 ListBox 已将名为的 listBox1控件添加到窗体中。
private:
   void DisplayHScroll()
   {
      // Make sure no items are displayed partially.
      listBox1->IntegralHeight = true;
      // Add items that are wide to the ListBox.
      for ( int x = 0; x < 10; x++ )
      {
         listBox1->Items->Add( String::Format( "Item {0} is a very large value that requires scroll bars", x ) );
      }
      // Display a horizontal scroll bar.
      listBox1->HorizontalScrollbar = true;
      // Create a Graphics object to use when determining the size of the largest item in the ListBox.
      Graphics^ g = listBox1->CreateGraphics();
      // Determine the size for HorizontalExtent using the MeasureString method using the last item in the list.
      int hzSize = (int)g->MeasureString( dynamic_cast<String^>(listBox1->Items[ listBox1->Items->Count - 1 ]), listBox1->Font ).Width;
      // Set the HorizontalExtent property.
      listBox1->HorizontalExtent = hzSize;
   }
private void DisplayHScroll()
{
   // Make sure no items are displayed partially.
   listBox1.IntegralHeight = true;
   // Add items that are wide to the ListBox.
   for (int x = 0; x < 10; x++)
   {
      listBox1.Items.Add("Item  " + x.ToString() + " is a very large value that requires scroll bars");
   }
   // Display a horizontal scroll bar.
   listBox1.HorizontalScrollbar = true;
   // Create a Graphics object to use when determining the size of the largest item in the ListBox.
   Graphics g = listBox1.CreateGraphics();
   // Determine the size for HorizontalExtent using the MeasureString method using the last item in the list.
   int hzSize = (int) g.MeasureString(listBox1.Items[listBox1.Items.Count -1].ToString(),listBox1.Font).Width;
   // Set the HorizontalExtent property.
   listBox1.HorizontalExtent = hzSize;
}
Private Sub DisplayHScroll()
     ' Make sure no items are displayed partially.
   listBox1.IntegralHeight = True
   Dim x As Integer
   ' Add items that are wide to the ListBox.
   For x = 0 To 10
      listBox1.Items.Add("Item  " + x.ToString() + " is a very large value that requires scroll bars")
   Next x
   ' Display a horizontal scroll bar.
   listBox1.HorizontalScrollbar = True
   ' Create a Graphics object to use when determining the size of the largest item in the ListBox.
   Dim g As System.Drawing.Graphics = listBox1.CreateGraphics()
   ' Determine the size for HorizontalExtent using the MeasureString method using the last item in the list.
   Dim hzSize As Integer = g.MeasureString(listBox1.Items(listBox1.Items.Count - 1).ToString(), listBox1.Font).Width
   ' Set the HorizontalExtent property.
   listBox1.HorizontalExtent = hzSize
End Sub
注解
如果属性设置为 true,HorizontalScrollbar则此属性仅报告有用的值。 如果宽度 ListBox 小于此属性的值,水平滚动条将水平滚动条中的 ListBox项。 如果宽度 ListBox 等于或大于此值,则隐藏水平滚动条。 此属性的值不会由 ListBox. 当所有者绘制的 ListBox 项时,此属性非常有用。 例如,如果所有者绘制的 ListBox 项宽为 200 像素,但 ListBox 宽度为 60 像素,则需要将 HorizontalExtent 属性设置为 200,以便将项的右边缘滚动到控件的可见区域。