Question

我在winforms表单上有一个listview控件。它填满了整个屏幕，但屏幕上显示的项目比屏幕更多。

如何截取整个控件的屏幕截图，就好像我可以在屏幕上显示listview的全部内容一样？因此，如果整个listview需要1000 x 4000像素，那么我想要一个这样大小的图像/位图。

我该怎么做？当我尝试打印屏幕时，它只返回屏幕上的内容，屏幕外的任何内容都显示为灰色。

Answer 1

表单是控件，因此您应该能够将整个内容保存到位图，例如：

var bm = new Bitmap(yourForm.Width, yourForm.Height);
yourForm.DrawToBitmap(bm, bm.Size);
bm.Save(@"c:\whatever.gif", ImageFormat.Gif);

更新

DrawToBitmap只能在屏幕上显示内容。如果要绘制列表的全部内容，则必须遍历列表以查找内容的大小，然后绘制每个项目。类似的东西：

var f = yourControl.Font;
var lineHeight = f.GetHeight();

// Find size of canvas
var s = new SizeF();
using (var g = yourControl.CreateGraphics())
{
    foreach (var item in yourListBox.Items)
    {
        s.Height += lineHeight ;
        var itemWidth = g.MeasureString(item.Text, f).Width;
        if (s.Width < itemWidth)
            s.Width = itemWidth;
    }
}

using( var canvas = new Bitmap(s) )
using( var g = Graphics.FromImage(canvas) )
{
    var pt = new PointF();
    foreach (var item in yourListBox.Items)
    {
        pt.Y += lineHeight ;
        g.DrawString(item.Text, f, Brushes.Black, pt);
    }

    canvas.Save(wherever);
}

Answer 2

除非你不喜欢爆炸，否则

Private Declare Function BitBlt Lib "gdi32" _
    (ByVal hDCDest As IntPtr, ByVal XDest As IntPtr, _
    ByVal YDest As IntPtr, ByVal nWidth As IntPtr, _
    ByVal nHeight As IntPtr, ByVal hDCSrc As IntPtr, _
    ByVal XSrc As IntPtr, ByVal YSrc As IntPtr, _
    ByVal dwRop As IntPtr) As IntPtr

Private Declare Function GetWindowDC Lib "user32" _
  (ByVal hWnd As IntPtr) As IntPtr

Private Declare Function ReleaseDC Lib "user32" _
  (ByVal hWnd As IntPtr, ByVal hdc As IntPtr) As IntPtr
Private Sub Blast()
    Dim dc As IntPtr
    dc = GetWindowDC(Me.Handle)
    Dim bm As Bitmap = New Bitmap(Me.Width, Me.Height)
    Dim g As Graphics = Graphics.FromImage(bm)
    Const vbSrcCopy = &HCC0020
    Dim gdc = g.GetHdc()
    BitBlt(gdc, 0, 0, Me.Width, Me.Height, dc, 0, 0, vbSrcCopy)
    g.ReleaseHdc()
    bm.Save("C:\yourfile.bmp", System.Drawing.Imaging.ImageFormat.Bmp)
    ReleaseDC(Me.Handle, dc)
End Sub

如何在C＃中截取Winforms控件/表单的屏幕截图？

2 个答案:

更新