如何正确处理居中的MDI窗体背景图像

不幸的是,似乎没有一个超快速的方法来做到这一点,但以下是我的解决方案,至少似乎不依赖巧合。

在MDI构造函数中,处理大小调整:

this.ResizeEnd += delegate { this.Refresh(); };

然后此重写处理最大化/还原事件

    protected override void WndProc(ref Message m)
    {
        if (m.Msg == Win32.WM_SYSCOMMAND)
        {
            int test = m.WParam.ToInt32() & 0xFFF0;
            switch (test)
            {
                case Win32.SC_MAXIMIZE:
                case Win32.SC_RESTORE:
                    this.Invalidate();  // used to keep background image centered
                    break;
            }
        }
        base.WndProc(ref m);
    }

常量值定义为:

    public const int WM_SYSCOMMAND =                    0x0112;
    //wparam for WM_SYSCOMMAND should be one of these after masking with 0xFFF0:
    public const int SC_RESTORE =                       0xF120;
    public const int SC_MINIMIZE =                      0xF020;
    public const int SC_MAXIMIZE =                      0xF030;

你可以做所有这些,或者你可以把 me.refresh 在MDI中 resize 事件。

在MDI窗体的Resize事件中调用positionContainerstoparentmiddle方法。 我没有测试过它,但它应该可以工作。您可能需要在“调整大小”事件中设置条件,以便在每次调整大小时停止图像位置更改。

   private void YourMDI_Resize(object sender, EventArgs e)
    {
        PositionContainersToParentMiddle();
    }

    private void PositionContainersToParentMiddle()
    {
        int iInitX = (ParentOfImage.Size.Width - YourImage.Size.Width) / 2;
        int iInitY = ( ParentOfImage.Location.Y + YourImage.Size.Height ) / 2;
        YourImage.Location = new Point( iInitX, iInitY ) ;

    }

Private Sub YourMDIFormName_Resize(ByVal sender As Object, ByVal e As EventArgs) Handles Me.Resize
    Me.BackgroundImage = My.Resources.YourBackgroundImageName
    Me.Refresh()
 End Sub

    private void Change_BackgroundImage(string _path)
  {
    string imagepath = _path;
    System.IO.FileStream fs;
 // MDI Form image background layout change her`enter code here`e     
 //(Remember control imagebakground layout take default form background layount )
          this.BackgroundImageLayout = ImageLayout.Center;
            // Checking File exists if yes go --->
            if (System.IO.File.Exists(imagepath))
            {
              // Read Image file
              fs = System.IO.File.OpenRead(imagepath);
                fs.Position = 0;
                // Change MDI From back ground picture
                foreach (Control ctl in this.Controls)
                {
                    if (ctl is MdiClient)
                    {
                      //ctl.BackColor = Color.AntiqueWhite;
                       ctl.BackColor = Color.FromArgb(31, 26, 23);
                       ctl.BackgroundImage = System.Drawing.Image.FromStream(fs);
                      break;
                       }
                  }
             }
          }