我在从我的 winform 应用程序中创建位图图像时遇到问题.

I have a problem on creating bitmap image out of my winform application.

情况:

我有一个名为CanvasControl"的 UserControl，它接受 OnPaint 方法作为我的 Draw Pad 应用程序的画布.在此用户控件中，我有一个函数PrintCanvas()"，它将创建 UserControl 的屏幕截图图像到 PNG 文件中.下面是 PrintCanvas() 函数:

I have a UserControl named as "CanvasControl" that accepts OnPaint method acting as canvas for my Draw Pad application. Inside this user control I have a function "PrintCanvas()" that will create a screenshot image of the UserControl into PNG file. Below is the PrintCanvas() function:

public void PrintCanvas(string filename = "sample.png")
{
    Graphics g = this.CreateGraphics();
    //new bitmap object to save the image        
    Bitmap bmp = new Bitmap(this.Width, this.Height);
    //Drawing control to the bitmap        
    this.DrawToBitmap(bmp, new Rectangle(0, 0, this.Width, this.Height));
    bmp.Save(Application.StartupPath + 
        @"ExperimentFilesExperiment1" + filename, ImageFormat.Png);
    bmp.Dispose();
}

这个用户控件(CanvasControl)在我的主窗体中被调用，用户将在其中绘制一些东西，然后可以选择使用保存按钮进行保存.保存按钮会调出UserControl的PrintCanvas()"函数.

This user control (CanvasControl) is called out inside my main form where user will draw something and have an option to save afterwards using a save button. The save button will call out the "PrintCanvas()" function of the UserControl.

我得到了预期的输出图像文件，但问题是它是一个空白图像.

I get the output image file as expected, but the problem is it was a blank image.

到目前为止我所尝试的:

What I have tried so far:

为了测试这不是语法问题，我尝试将 PrintCanvas() 函数转移到我的主窗体中，令人惊讶的是，我在文件中获得了整个主窗体的图像，但 UserControl 在那里不可见.

To test that it is not a syntax issue, I tried to transfer the PrintCanvas() function into my main form and surprisingly I get an image of the whole main form on file but the UserControl is not visible there.

我是否错过了任何其他设置以使 winform UserControl 可打印?

Is there any other setup i missed out to make a winform UserControl printable?

更新:(绘图程序)

推荐答案

问题中的代码给出了第一个提示，但链接中的代码显示了问题的根源:您使用了