DrawItemState 列舉

定義

命名空間:

System.Windows.Forms

組件:

System.Windows.Forms.dll

指定所繪製項目的狀態。

此列舉支援其成員值的位元組合。

C#

[System.Flags]
public enum DrawItemState

繼承

Object

ValueType

Enum

DrawItemState

屬性

FlagsAttribute

欄位

名稱	值	Description
Checked	8	已選取這個項目。 只有功能表控制項使用這個值。
ComboBoxEdit	4096	這個項目是 ComboBox 的編輯部分。
Default	32	這個項目處於預設的可見狀態。
Disabled	4	這個項目無法使用。
Focus	16	項目已取得焦點。
Grayed	2	這個項目呈灰色。 只有功能表控制項使用這個值。
HotLight	64	這個項目正被熱追蹤，也就是說，這個項目在滑鼠指標通過時會反白顯示。
Inactive	128	這個項目非現用。
NoAccelerator	256	這個項目沒有鍵盤快速鍵也可顯示。
NoFocusRect	512	這個項目沒有指示有焦點的視覺提示也可顯示。
None	0	這個項目目前沒有狀態。
Selected	1	這個項目已選取。

範例

下列程式碼範例示範如何使用 Graphics 屬性，在 中 ListBox 執行專案的自訂繪圖。

C#

public class Form1 : System.Windows.Forms.Form
{
   private System.Windows.Forms.ListBox listBox1;
   private System.ComponentModel.Container components = null;

   protected override void Dispose(bool disposing)
   {
      if( disposing )
      {
         if ( components != null ) 
            components.Dispose();

         if ( foreColorBrush != null )
            foreColorBrush.Dispose();
      }
      base.Dispose(disposing);
   }

     #region Windows Form Designer generated code
   /// <summary>
   /// Required method for Designer support - do not modify
   /// the contents of this method with the code editor.
   /// </summary>
   private void InitializeComponent()
   {
      this.listBox1 = new System.Windows.Forms.ListBox();
      this.SuspendLayout();
      // 
      // listBox1
      // 
      this.listBox1.DrawMode = System.Windows.Forms.DrawMode.OwnerDrawVariable;
      this.listBox1.Location = new System.Drawing.Point(16, 48);
      this.listBox1.Name = "listBox1";
      this.listBox1.SelectionMode = System.Windows.Forms.SelectionMode.MultiExtended;
      this.listBox1.Size = new System.Drawing.Size(256, 134);
      this.listBox1.TabIndex = 0;
      this.listBox1.MeasureItem += new System.Windows.Forms.MeasureItemEventHandler(this.listBox1_MeasureItem);
      this.listBox1.DrawItem += new System.Windows.Forms.DrawItemEventHandler(this.listBox1_DrawItem);
      // 
      // Form1
      // 
      this.ClientSize = new System.Drawing.Size(292, 273);
      this.Controls.AddRange(new System.Windows.Forms.Control[] {
                                                                   this.listBox1});
      this.Name = "Form1";
      this.Text = "Form1";
      this.ResumeLayout(false);
   }
     #endregion

   [STAThread]
   static void Main() 
   {
      Application.Run(new Form1());
   }

   private void listBox1_MeasureItem(object sender, System.Windows.Forms.MeasureItemEventArgs e)
   {
      Font font = ((ListBoxFontItem)listBox1.Items[e.Index]).Font;
      SizeF stringSize = e.Graphics.MeasureString(font.Name, font);

      // Set the height and width of the item
      e.ItemHeight = (int)stringSize.Height;
      e.ItemWidth = (int)stringSize.Width;
   }

   // For efficiency, cache the brush to use for drawing.
   private SolidBrush foreColorBrush;

   private void listBox1_DrawItem(object sender, System.Windows.Forms.DrawItemEventArgs e)
   {
      Brush brush;

      // Create the brush using the ForeColor specified by the DrawItemEventArgs
      if ( foreColorBrush == null )
         {
             foreColorBrush = new SolidBrush(e.ForeColor);
         }
         else if ( foreColorBrush.Color != e.ForeColor )
      {
         // The control's ForeColor has changed, so dispose of the cached brush and
         // create a new one.
         foreColorBrush.Dispose();
         foreColorBrush = new SolidBrush(e.ForeColor);
      }

      // Select the appropriate brush depending on if the item is selected.
      // Since State can be a combinateion (bit-flag) of enum values, you can't use
      // "==" to compare them.
      if ( (e.State & DrawItemState.Selected) == DrawItemState.Selected )
         brush = SystemBrushes.HighlightText;
      else
         brush = foreColorBrush;

      // Perform the painting.
      Font font = ((ListBoxFontItem)listBox1.Items[e.Index]).Font;
      e.DrawBackground();
      e.Graphics.DrawString(font.Name, font, brush, e.Bounds);
      e.DrawFocusRectangle();
   }

   /// <summary>
   ///  A wrapper class for use with storing Fonts in a ListBox.  Since ListBox uses the
   ///  ToString() of its items for the text it displays, this class is needed to return
   ///  the name of the font, rather than its ToString() value.
   /// </summary>
   public class ListBoxFontItem 
   {
      public Font Font;

      public ListBoxFontItem(Font f) 
      {
         Font = f;
      }

      public override string ToString() 
      {
         return Font.Name;
      }
   }
}

備註

這類成員 DrawItemEventArgs.State 會使用此列舉。

適用於

另請參閱

• DrawItemEventArgs