c# - 儿童控制和键盘箭头、退格键等

Question

我把 3TextBoxes放在里面，DataGridView.我可以集中它们并输入文本。但是当我尝试使用箭头在 TexBox 内移动光标时，DataGridView 会窃取箭头键，并在网格中移动单元格选择。如何预防？

Answer 1

在尝试了一些覆盖默认键行为的艰难尝试后DataGridView，我最终得到了这个变通办法、棘手和 hacky 的解决方案。就像您控制TextBox. 抑制Key messageonDataGridView很容易，但不知何故，子控件不能受这些关键消息的影响，尽管它可以接收这些消息。那很奇怪。我真的很想知道这个问题最漂亮和最直接的解决方案，如果有人知道，请添加您的答案或留下一些参考链接作为您的评论。那将不胜感激。正如我所说，这是我拥有的代码，它既棘手又笨拙，但效果很好：

//This helper class to use some Win32 functions, must add using System.Runtime.InteropServices;
public class Win32 {
    [DllImport("user32")]
    public static extern bool GetCaretPos(out POINT pos);
    [DllImport("user32")]
    public static extern bool SetCaretPos(int x, int y);
    [DllImport("user32")]
    public static extern int SendMessage(IntPtr hwnd, int msg, IntPtr wParam, IntPtr lParam);
    public struct POINT {
        public int x, y;
    }
}
//This is the extension class for TextBox, it's just for convenience
public static class TextBoxExtension {
    public static void BeginUpdate(this TextBox text) {
        Win32.SendMessage(text.Handle, 0xb, IntPtr.Zero, IntPtr.Zero);
    }
    public static void EndUpdate(this TextBox text) {
        Win32.SendMessage(text.Handle, 0xb, new IntPtr(1), IntPtr.Zero);
    }
    public static int GetCaretCharIndex(this TextBox text){
        Win32.POINT p;
        Win32.GetCaretPos(out p);
        return text.GetCharIndexFromPosition(new Point(p.x, p.y));
    }
    public static void SetCaretCharIndex(this TextBox text, int charIndex) {
        Point p = text.GetPositionFromCharIndex(charIndex);
        Win32.SetCaretPos(p.X, p.Y);
    }
    public static void ProcessRight(this TextBox text, bool shiftPressed) {
        if (shiftPressed) {
            int lastEndIndex = text.SelectionStart + text.SelectionLength;
            int caretCharIndex = text.GetCaretCharIndex();
            if (caretCharIndex == lastEndIndex || (caretCharIndex == text.TextLength-1 && text.SelectionLength > 1)){
                text.SelectionLength++;                    
            } else {
                text.BeginUpdate();
                text.SelectionStart++;                    
                if (lastEndIndex < text.TextLength) text.SelectionLength--;
                text.EndUpdate();
                text.Refresh();
                if (text.SelectionStart < text.TextLength) text.SetCaretCharIndex(text.SelectionStart);
            } 
        } else {
            if (text.SelectionLength > 0) {
                int s = text.SelectionLength;
                text.SelectionLength = 0;
                text.SelectionStart += s;
            }
            else if (text.SelectionStart < text.TextLength) text.SelectionStart++; 
        }
    }
    public static void ProcessLeft(this TextBox text, bool shiftPressed) {
        if (shiftPressed) {
            if (text.GetCaretCharIndex() == text.SelectionStart || text.SelectionStart == text.TextLength) {
                if (text.SelectionStart > 0) {
                    text.BeginUpdate();
                    text.SelectionStart--;
                    text.SelectionLength++;                                                                        
                    text.EndUpdate();
                    text.Refresh();
                    text.SetCaretCharIndex(text.SelectionStart);
                }
            } else {
                text.SelectionLength--;
            }
        } else {
            if (text.SelectionStart > 0 && text.SelectionLength == 0) text.SelectionStart--;
            text.SelectionLength = 0;
        }
    }
    public static void ProcessHome(this TextBox text, bool shiftPressed) {
        if (shiftPressed) {
            int i = text.SelectionStart;
            text.SelectionStart = 0;
            text.SelectionLength = i;
            text.SetCaretCharIndex(0);
        } else {
            text.SelectionLength = 0;
            text.SelectionStart = 0;
        }
    }
    public static void ProcessEnd(this TextBox text, bool shiftPressed) {
        if (shiftPressed) {
            text.SelectionLength = text.TextLength - text.SelectionStart;
        } else {
            text.SelectionLength = 0;
            text.SelectionStart = text.TextLength;
        }
    }
    public static void ProcessDelete(this TextBox text) {
        if (text.SelectionLength == 0) text.SelectionLength = 1;
        text.SelectedText = "";
    }
}

//your custom DataGridView
public class CustomDGV : DataGridView { 
    public event EventHandler InnerTextBoxEnterKeyPress;         
    protected override bool ProcessCmdKey(ref Message msg, Keys keyData) {
        TextBox childControl = Controls.OfType<TextBox>().FirstOrDefault(c=>c.Focused);
        if (childControl != null) {                
            bool suppress = true;
            switch (keyData) {
                case Keys.Right:
                    childControl.ProcessRight(false);
                    break;
                case Keys.Shift | Keys.Right:
                    childControl.ProcessRight(true);
                    break;
                case Keys.Left:
                    childControl.ProcessLeft(false);
                    break;
                case Keys.Shift | Keys.Left:
                    childControl.ProcessLeft(true);
                    break;
                case Keys.End:
                    childControl.ProcessEnd(false);
                    break;
                case Keys.Home:
                    childControl.ProcessHome(false);
                    break;
                case Keys.Delete:
                    childControl.ProcessDelete();
                    break;
                case Keys.Shift | Keys.End:
                    childControl.ProcessEnd(true);
                    break;
                case Keys.Shift | Keys.Home:
                    childControl.ProcessHome(true);
                    break;
                case Keys.Control | Keys.C:
                    childControl.Copy();
                    break;
                case Keys.Control | Keys.X:
                    childControl.Cut();
                    break;
                case Keys.Control | Keys.V:
                    childControl.Paste();
                    break;
                case Keys.Enter:
                    EventHandler handler = InnerTextBoxEnterKeyPress;
                    if (handler != null) InnerTextBoxEnterKeyPress(childControl, EventArgs.Empty);
                    Focus();
                    break;
                default:
                    suppress = false;
                    break;
            }                
            if (suppress) return true;                
        }
        return base.ProcessCmdKey(ref msg, keyData);
    }        
}

注意：我还添加了一个名为 的事件，您可以注册此事件以在用户在网格InnerTextBoxEnterKeyPress内部按 Enter 时执行您自己的行为，如下所示：TextBox

customDGV1.InnerTextBoxEnterKeyPress += (s,e) => {
  TextBox text = s as TextBox;
  //your code goes here ... try showing some message to see it in action
  MessageBox.Show(text.Text);
};