Winforms-如何打印整个表单，包括看不见的部分？ [英] Winforms - how to print the whole of a form, including unseen parts?

问题描述

我有一个用C＃编写的Windows窗体项目。主窗体上有 TabControl ，并且要求其中一个用户能够打印 TabPages 。表格很长，我使用垂直滚动条。

I have a windows forms project written in C#. The main form has a TabControl on it and there is a requirement for one of the users to be able to print one of the TabPages. The form is very long and I use a vertical scroll bar. The whole of the form needs to be able to be printed.

我尝试使用 DrawToBitmap 方法进行转换到位图，但这只会包括用户可以看到的部分形式。我尝试过的其他一些解决方案也涉及到屏幕捕获，这也存在相同的问题。

I have tried using the DrawToBitmap method to convert to a bitmap first, but this will only include the portion of the form that the user can see. Some other solutions I have tried involve screen capturing, which has the same issue.

如何打印或获取整个标签页的图像，包括用户向下滚动时只能看到的部分？

How can I print out, or get an image, of the whole of the tab page, including the parts the user only sees when they scroll down?

推荐答案

对于包括 TabControls 和 TabPages ，但不包含 Forms 。

This is rather simple for any control including TabControls and TabPages but not Forms.

您需要做的就是放大相关控件以显示其所有内容。 （他们不必实际上必须在屏幕上可见。）

All you need to do is enlarge the relevant controls enough to show all their content. (They don't have to be actually visible on screen.)

这里是一个例子：

tabControl1.Height = 10080;
tabPage2.Height = 10050;
dataGridView1.Height = 10000;

dataGridView1.Rows.Add(3000);
for (int i = 0; i < dataGridView1.Rows.Count; i++)  dataGridView1[0, i].Value = i;

using (Bitmap bmp = new Bitmap(tabControl1.Width , tabControl1.Height ))
{
    tabControl1.DrawToBitmap(bmp, tabControl1.ClientRectangle);
    bmp.Save("D:\\xxxx.png", ImageFormat.Png);
}

这将保存 DataGridView的全部内容， TabPage 和 TabControl ..

注意：：这不适用于表单，表单不能超出屏幕尺寸。.

Note: that this will not work with forms, which can't much exceed the screen dimensions..

更新：这是通过将多个位图修补在一起来保存垂直滚动表单的代码。当然，它也可以扩展为包括水平滚动。我已经为大型面板此处。

Update: Here is code that saves a form with vertical scrolling by patching several bitmaps together. It can, of course be expanded to include horizontal scrolling as well. I have coded a similar solution for larger Panels here.

static void saveLargeForm(Form form, string fileName)
{
    // yes it may take a while
    form.Cursor = Cursors.WaitCursor;

    // allocate target bitmap and a buffer bitmap
    Bitmap target = new Bitmap(form.DisplayRectangle.Width, form.DisplayRectangle.Height);
    Bitmap buffer = new Bitmap(form.Width, form.Height);
    // the vertical pointer
    int y = 0;
    var vsc = form.VerticalScroll;
    vsc.Value = 0;
    form.AutoScrollPosition = new Point(0, 0);
    // the scroll amount
    int l = vsc.LargeChange;

    Rectangle srcRect = ClientBounds(form);
    Rectangle destRect = Rectangle.Empty;
    bool done = false;

    // we'll draw onto the large bitmap with G
    using (Graphics G = Graphics.FromImage(target))
    {
        while (!done)
        {
            destRect = new Rectangle(0, y, srcRect.Width, srcRect.Height);
            form.DrawToBitmap(buffer, new Rectangle(0, 0, form.Width, form.Height));
            G.DrawImage(buffer, destRect, srcRect, GraphicsUnit.Pixel);   
            int v = vsc.Value;
            vsc.Value = vsc.Value + l;
            form.AutoScrollPosition = new Point(form.AutoScrollPosition.X, vsc.Value + l);
            int delta = vsc.Value - v;
            done = delta < l;
            y += delta;
        }
        destRect = new Rectangle(0, y, srcRect.Width, srcRect.Height);
        form.DrawToBitmap(buffer, new Rectangle(0, 0, form.Width, form.Height));
        G.DrawImage(buffer, destRect, srcRect, GraphicsUnit.Pixel);
    }
    // write result to disc and clean up
    target.Save(fileName, System.Drawing.Imaging.ImageFormat.Png);
    target.Dispose();   
    buffer.Dispose();      
    GC.Collect();          // not sure why, but it helped
    form.Cursor = Cursors.Default;    
}

它使用辅助函数来确定虚拟设备的净大小客户矩形，即不包括边框，标题和滚动条：

It makes use of a helper function to determine the the net size of the virtual client rectangle, ie excluding borders, title and scrollbar:

static Rectangle ClientBounds(Form f)
{
    Rectangle rc = f.ClientRectangle;
    Rectangle rb = f.Bounds;
    int sw = SystemInformation.VerticalScrollBarWidth;
    var vsc = f.VerticalScroll;
    int bw = (rb.Width - rc.Width - (vsc.Visible ? sw : 0) ) / 2;
    int th = (rb.Height - rc.Height) - bw * 2;
    return new Rectangle(bw, th + bw, rc.Width, rc.Height );
}

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