ComboBox.DrawItem 이벤트

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정의

네임스페이스:
System.Windows.Forms
어셈블리:
System.Windows.Forms.dll

소유자가 그린 ComboBox의 시각적 측면이 변경될 때 발생합니다.

public:
 event System::Windows::Forms::DrawItemEventHandler ^ DrawItem;
public event System.Windows.Forms.DrawItemEventHandler DrawItem;
public event System.Windows.Forms.DrawItemEventHandler? DrawItem;
member this.DrawItem : System.Windows.Forms.DrawItemEventHandler 
Public Custom Event DrawItem As DrawItemEventHandler

이벤트 유형

DrawItemEventHandler

예제

다음 코드 예제에서는 속성을 로 설정하고 DrawModeOwnerDrawnVariable 및 MeasureItem 이벤트를 처리 DrawItem 하여 소유자가 그린 콤보 상자를 만드는 방법을 보여 줍니다. 또한 및 DropDownStyle 속성을 설정하는 방법을 DropDownWidth 보여 줍니다. 예제를 실행 하는 폼에 다음 코드를 붙여넣습니다. 폼의 InitializeComboBox 생성자 또는 Load 이벤트에서 메서드를 호출합니다.

internal:
   System::Windows::Forms::ComboBox^ ComboBox1;

private:
   array<String^>^ animals;

   // This method initializes the owner-drawn combo box.
   // The drop-down width is set much wider than the size of the combo box
   // to accomodate the large items in the list.  The drop-down style is set to 
   // ComboBox.DropDown, which requires the user to click on the arrow to 
   // see the list.
   void InitializeComboBox()
   {
      this->ComboBox1 = gcnew ComboBox;
      this->ComboBox1->DrawMode = System::Windows::Forms::DrawMode::OwnerDrawVariable;
      this->ComboBox1->Location = System::Drawing::Point( 10, 20 );
      this->ComboBox1->Name = "ComboBox1";
      this->ComboBox1->Size = System::Drawing::Size( 100, 120 );
      this->ComboBox1->DropDownWidth = 250;
      this->ComboBox1->TabIndex = 0;
      this->ComboBox1->DropDownStyle = ComboBoxStyle::DropDown;
      animals = gcnew array<String^>{"Elephant","c r o c o d i l e","lion"};
      ComboBox1->DataSource = animals;
      this->Controls->Add( this->ComboBox1 );
      
      // Hook up the MeasureItem and DrawItem events
      this->ComboBox1->DrawItem +=
         gcnew DrawItemEventHandler( this, &Form1::ComboBox1_DrawItem );
      this->ComboBox1->MeasureItem +=
         gcnew MeasureItemEventHandler( this, &Form1::ComboBox1_MeasureItem );
   }

   // If you set the Draw property to DrawMode.OwnerDrawVariable, 
   // you must handle the MeasureItem event. This event handler 
   // will set the height and width of each item before it is drawn. 
private:
   void ComboBox1_MeasureItem( Object^ sender,
      System::Windows::Forms::MeasureItemEventArgs^ e )
   {
      switch ( e->Index )
      {
         case 0:
            e->ItemHeight = 45;
            break;
         case 1:
            e->ItemHeight = 20;
            break;
         case 2:
            e->ItemHeight = 35;
            break;
      }
      e->ItemWidth = 260;
   }

private:
   // You must handle the DrawItem event for owner-drawn combo boxes.  
   // This event handler changes the color, size and font of an 
   // item based on its position in the array.
   void ComboBox1_DrawItem( Object^ sender,
      System::Windows::Forms::DrawItemEventArgs^ e )
   {
      float size = 0;
      System::Drawing::Font^ myFont;
      FontFamily^ family = nullptr;

      System::Drawing::Color animalColor;
      switch ( e->Index )
      {
         case 0:
            size = 30;
            animalColor = System::Drawing::Color::Gray;
            family = FontFamily::GenericSansSerif;
            break;
         case 1:
            size = 10;
            animalColor = System::Drawing::Color::LawnGreen;
            family = FontFamily::GenericMonospace;
            break;
         case 2:
            size = 15;
            animalColor = System::Drawing::Color::Tan;
            family = FontFamily::GenericSansSerif;
            break;
      }

      // Draw the background of the item.
      e->DrawBackground();
      
      // Create a square filled with the animals color. Vary the size
      // of the rectangle based on the length of the animals name.
      Rectangle rectangle = Rectangle( 2, e->Bounds.Top + 2,
         e->Bounds.Height, e->Bounds.Height - 4 );
      e->Graphics->FillRectangle( gcnew SolidBrush( animalColor ), rectangle );
      
      // Draw each string in the array, using a different size, color,
      // and font for each item.
      myFont = gcnew System::Drawing::Font( family, size, FontStyle::Bold );
      e->Graphics->DrawString( animals[ e->Index ], myFont,
         System::Drawing::Brushes::Black, RectangleF(
            e->Bounds.X + rectangle.Width, e->Bounds.Y,
            e->Bounds.Width, e->Bounds.Height) );
      
      // Draw the focus rectangle if the mouse hovers over an item.
      e->DrawFocusRectangle();
   }


  internal System.Windows.Forms.ComboBox ComboBox1;
  private string[] animals;

  // This method initializes the owner-drawn combo box.
  // The drop-down width is set much wider than the size of the combo box
  // to accomodate the large items in the list.  The drop-down style is set to 
  // ComboBox.DropDown, which requires the user to click on the arrow to 
  // see the list.
  private void InitializeComboBox()
  {
      this.ComboBox1 = new ComboBox();
      this.ComboBox1.DrawMode = 
          System.Windows.Forms.DrawMode.OwnerDrawVariable;
      this.ComboBox1.Location = new System.Drawing.Point(10, 20);
      this.ComboBox1.Name = "ComboBox1";
      this.ComboBox1.Size = new System.Drawing.Size(100, 120);
      this.ComboBox1.DropDownWidth = 250;
      this.ComboBox1.TabIndex = 0;
      this.ComboBox1.DropDownStyle = ComboBoxStyle.DropDown;
      animals = new string[]{"Elephant", "c r o c o d i l e", "lion"};
      ComboBox1.DataSource = animals;
      this.Controls.Add(this.ComboBox1);

      // Hook up the MeasureItem and DrawItem events
      this.ComboBox1.DrawItem += 
          new DrawItemEventHandler(ComboBox1_DrawItem);
      this.ComboBox1.MeasureItem += 
          new MeasureItemEventHandler(ComboBox1_MeasureItem);
  }

  // If you set the Draw property to DrawMode.OwnerDrawVariable, 
  // you must handle the MeasureItem event. This event handler 
  // will set the height and width of each item before it is drawn. 
  private void ComboBox1_MeasureItem(object sender, 
      System.Windows.Forms.MeasureItemEventArgs e)
  {

      switch(e.Index)
      {
          case 0:
              e.ItemHeight = 45;
              break;
          case 1:
              e.ItemHeight = 20;
              break;
          case 2:
              e.ItemHeight = 35;
              break;
      }
      e.ItemWidth = 260;
  }

  // You must handle the DrawItem event for owner-drawn combo boxes.  
  // This event handler changes the color, size and font of an 
  // item based on its position in the array.
  private void ComboBox1_DrawItem(object sender, 
      System.Windows.Forms.DrawItemEventArgs e)
  {

      float size = 0;
      System.Drawing.Font myFont;
      FontFamily family = null;

      System.Drawing.Color animalColor = new System.Drawing.Color();
      switch(e.Index)
      {
          case 0:
              size = 30;
              animalColor = System.Drawing.Color.Gray;
              family = FontFamily.GenericSansSerif;
              break;
          case 1:
              size = 10;
              animalColor = System.Drawing.Color.LawnGreen;
              family = FontFamily.GenericMonospace;
              break;
          case 2:
              size = 15;
              animalColor = System.Drawing.Color.Tan;
              family = FontFamily.GenericSansSerif;
              break;
      }

      // Draw the background of the item.
      e.DrawBackground();

      // Create a square filled with the animals color. Vary the size
      // of the rectangle based on the length of the animals name.
      Rectangle rectangle = new Rectangle(2, e.Bounds.Top+2, 
              e.Bounds.Height, e.Bounds.Height-4);
      e.Graphics.FillRectangle(new SolidBrush(animalColor), rectangle);

      // Draw each string in the array, using a different size, color,
      // and font for each item.
      myFont = new Font(family, size, FontStyle.Bold);
      e.Graphics.DrawString(animals[e.Index], myFont, System.Drawing.Brushes.Black, new RectangleF(e.Bounds.X+rectangle.Width, e.Bounds.Y, e.Bounds.Width, e.Bounds.Height));

      // Draw the focus rectangle if the mouse hovers over an item.
      e.DrawFocusRectangle();
  }


  Friend WithEvents ComboBox1 As System.Windows.Forms.ComboBox
  Private animals() As String

  ' This method initializes the owner-drawn combo box.
  ' The drop-down width is set much wider than the size of the combo box
  ' to accomodate the large items in the list.  The drop-down style is set to 
  ' ComboBox.DropDown, which requires the user to click on the arrow to 
  ' see the list.
  Private Sub InitializeComboBox()
      Me.ComboBox1 = New ComboBox
      Me.ComboBox1.DrawMode = System.Windows.Forms.DrawMode.OwnerDrawVariable
      Me.ComboBox1.Location = New System.Drawing.Point(10, 20)
      Me.ComboBox1.Name = "ComboBox1"
      Me.ComboBox1.Size = New System.Drawing.Size(100, 120)
      Me.ComboBox1.DropDownWidth = 250
      Me.ComboBox1.TabIndex = 0
      Me.ComboBox1.DropDownStyle = ComboBoxStyle.DropDown
      animals = New String() {"Elephant", "c r o c o d i l e", "lion"}
      ComboBox1.DataSource = animals
      Me.Controls.Add(Me.ComboBox1)
  End Sub

  ' If you set the Draw property to DrawMode.OwnerDrawVariable, 
  ' you must handle the MeasureItem event. This event handler 
  ' will set the height and width of each item before it is drawn. 
   Private Sub ComboBox1_MeasureItem(ByVal sender As Object, _
      ByVal e As System.Windows.Forms.MeasureItemEventArgs) _
          Handles ComboBox1.MeasureItem

      Select Case e.Index
          Case 0
              e.ItemHeight = 45
          Case 1
              e.ItemHeight = 20
          Case 2
              e.ItemHeight = 35
      End Select
      e.ItemWidth = 260

  End Sub

  ' You must handle the DrawItem event for owner-drawn combo boxes.  
  ' This event handler changes the color, size and font of an 
  ' item based on its position in the array.
  Private Sub ComboBox1_DrawItem(ByVal sender As Object,  _ 
      ByVal e As System.Windows.Forms.DrawItemEventArgs) _
      Handles ComboBox1.DrawItem

      Dim size As Single
      Dim myFont As System.Drawing.Font
      Dim family As FontFamily

      Dim animalColor As New System.Drawing.Color
      Select Case e.Index
          Case 0
              size = 30
              animalColor = System.Drawing.Color.Gray
              family = FontFamily.GenericSansSerif
          Case 1
              size = 10
              animalColor = System.Drawing.Color.LawnGreen
              family = FontFamily.GenericMonospace
          Case 2
              size = 15
              animalColor = System.Drawing.Color.Tan
              family = FontFamily.GenericSansSerif
      End Select

      ' Draw the background of the item.
      e.DrawBackground()

      ' Create a square filled with the animals color. Vary the size
      ' of the rectangle based on the length of the animals name.
      Dim rectangle As Rectangle = New Rectangle(2, e.Bounds.Top + 2, _
          e.Bounds.Height, e.Bounds.Height - 4)
      e.Graphics.FillRectangle(New SolidBrush(animalColor), rectangle)

      ' Draw each string in the array, using a different size, color,
      ' and font for each item.
      myFont = New Font(family, size, FontStyle.Bold)
      e.Graphics.DrawString(animals(e.Index), myFont, System.Drawing.Brushes.Black, _
          New RectangleF(e.Bounds.X + rectangle.Width, e.Bounds.Y, _ 
          e.Bounds.Width, e.Bounds.Height))

      ' Draw the focus rectangle if the mouse hovers over an item.
      e.DrawFocusRectangle()
  End Sub

설명

이 이벤트는 소유자가 그린 사용한 ComboBox합니다. 이 이벤트를 사용하여 에서 항목을 그리는 데 필요한 작업을 수행할 수 있습니다 ComboBox. 변수 크기 항목이 있는 경우(속성이 ComboBox.DrawMode 값System.Windows.Forms.DrawMode으로 OwnerDrawVariable 설정된 경우) 항목을 MeasureItem 그리기 전에 이벤트가 발생합니다. 이벤트에 대한 이벤트 처리기를 만들어 이벤트에 대한 MeasureItem 이벤트 처리기 DrawItem 에서 그릴 항목의 크기를 지정할 수 있습니다.

이벤트 처리에 대한 자세한 내용은 이벤트 처리 및 발생 을 참조하십시오.

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