繪製自己的標題欄

Question

我畫的標題欄的一部分，在我WinForm的應用。好的工作（將公司集中橙和名稱）

這是代碼做，在表單代碼：

using System.Runtime.InteropServices; 


    [DllImport("user32.dll")] 
    private static extern IntPtr GetWindowDC(IntPtr hWnd); 

    [DllImport("user32.dll")] 
    private static extern int ReleaseDC(IntPtr hWnd, IntPtr hDC); 



    private Rectangle PosicionTexto() 
    { 
    string sTexto = String.Format("{0} : {1}", this.Text, "Trevo I.T."); 
    sTexto = "Trevo I.T."; 

    Graphics oG = this.CreateGraphics(); 

    SizeF oS = oG.MeasureString(sTexto, new Font("Tahoma", 8f, FontStyle.Bold)); 

    Rectangle rect = new Rectangle(); 
    rect.X = (this.Width/2) - (int)(oS.Width/2); 
    rect.Y = SystemInformation.FrameBorderSize.Height + 4; 
    rect.Width = (int)oS.Width; 
    rect.Height = SystemInformation.CaptionButtonSize.Height; 

    return rect; 
    } 

    private void DrawTitleBar(IntPtr hwnd) 
    { 
    // Obtenemos el Canvas a partir del DC de la ventana 
    IntPtr hdc = GetWindowDC(hwnd); 
    Graphics gBarra = Graphics.FromHdc(hdc); 

    Rectangle rect = PosicionTexto(); 
    string sTexto = String.Format("{0} : {1}", this.Text, "Trevo I.T."); 
    sTexto = "Trevo I.T."; 
    gBarra.DrawString(sTexto, new Font("Tahoma", 8f, FontStyle.Bold), Brushes.Orange, new PointF(rect.X, rect.Y)); 

    // Liberamos la memoria*/ 
    gBarra.Flush(); 
    ReleaseDC(hwnd, hdc); 
    } 

    protected override void WndProc(ref Message m) 
    { 
    switch (m.Msg) 
    { 
     case 0x000F: // WM_PAINT 
     case 0x0085: // WM_NCPAINT: 
      base.WndProc(ref m); 
      DrawTitleBar(m.HWnd); 
      break; 

     default: 
      // Invocamos a la funcion original 
      base.WndProc(ref m); 
      break; 
    } 
    } 

的問題是調整窗口的大小。文本不會被清除並顯示多次。有沒有辦法在繪製文字之前「刷新」標題欄？

在此先感謝。

編輯 幾乎解決了。增加了兩個方法：

// Rectangle of the title bar 
    private Rectangle TitleBarRectangle() 
     { 
     Rectangle rect = new Rectangle(); 
     rect.X = 1 + SystemInformation.CaptionButtonSize.Width; // Avoid to draw over the icon 
     rect.Y = 1; 
     rect.Width = Width - (SystemInformation.CaptionButtonSize.Width * 4); // Avoid to draw over the buttons 
     rect.Height = SystemInformation.CaptionButtonSize.Height; 
     return rect; 
     } 

    // Draw a filled rectangle 
    private void ClearTitleBar(IntPtr hwnd) 
    { 
    // Obtenemos el Canvas a partir del DC de la ventana 
    IntPtr hdc = GetWindowDC(hwnd); 

    try 
    { 
     using (Graphics gBarra = Graphics.FromHdc(hdc)) 
     { 
      Rectangle rect = TitleBarRectangle(); 
      gBarra.FillRectangle(new SolidBrush(SystemColors.ActiveCaption), rect); 
      gBarra.Flush(); 
     } 
    } 
    finally 
    { 
     ReleaseDC(hwnd, hdc); 
    } 
    } 

和修改一個：

protected override void WndProc(ref Message m) 
    { 
    switch (m.Msg) 
    { 
     case 0x0085: // WM_NCPAINT: 
     case 0x0005: // WM_SIZE 
      base.WndProc(ref m); 
      DrawTitleBar(m.HWnd); 
      break; 

     case 0x214: // WM_SIZING 
      base.WndProc(ref m); 
      ClearTitleBar(m.HWnd); 
      break; 

     default: 
      // Invocamos a la funcion original 
      base.WndProc(ref m); 
      break; 
    } 
    } 

順便說一句，這個念頭從Copstone

感謝拉斯，扎克當然，吉姆開始。你的意見和答案讓我走上了正軌。

Answer 1

一個簡單的解決方法是調用gBarra.FillRectangle填寫標題欄的背景顏色，你畫的字符串之前。

你確定你需要做的這WM_PAINT？看起來像WM_NCPAINT就足夠了。

我強烈建議您使用try...finally，以確保DC得到釋放。那就是：

private void DrawTitleBar(IntPtr hwnd) 
{ 
    // Obtenemos el Canvas a partir del DC de la ventana 
    IntPtr hdc = GetWindowDC(hwnd); 
    try 
    { 
     using (Graphics gBarra = Graphics.FromHdc(hdc)) 
     { 
      Rectangle rect = PosicionTexto(); 
      string sTexto = String.Format("{0} : {1}", this.Text, "Trevo I.T."); 
      sTexto = "Trevo I.T."; 
      gBarra.DrawString(sTexto, new Font("Tahoma", 8f, FontStyle.Bold), Brushes.Orange, new PointF(rect.X, rect.Y)); 

      // Liberamos la memoria*/ 
      gBarra.Flush(); 
     } 
    } 
    finally 
    { 
     ReleaseDC(hwnd, hdc); 
    } 
}