Question

在粘贴到文本框C＃（Ctrl + V和右键单击 - ＆gt;粘贴）之前，是否有一些方法可以在剪贴板中仅检查剪贴板中的字符数，而不使用MarkedTextbox。

Answer 1

在文本框文本中添加规则更改为仅接受数字：

        private string value;
             private void textBox1_TextChanged(object sender, EventArgs e)
                {
                    // at this moment value is still old 
                    var oldValue = value;  
                    if (System.Text.RegularExpressions.Regex.IsMatch(textBox1.Text, "[^0-9]"))
                    {
                        MessageBox.Show("Please enter numbers only.");
                        textBox1.Text = oldvalue;
                    }
                    else{
                        value = ((TextBox)sender).Text;
                    }
                }

Answer 2

我怀疑在粘贴到TextBox之前有任何检查，我建议订阅KeyDown和MouseClick事件，并编写自己的逻辑。

protected override void OnKeyDown(object sender, KeyEventArgs e)
{
     if (e.KeyCode == Keys.V && e.Modifiers == Keys.Control)
     {
           // Your logic to read clipboard content and check length.;
     }     
}

private void Form1_MouseClick(object sender, MouseEventArgs e)
{ 
     if (e.Button == System.Windows.Forms.MouseButtons.Right)
     {
          // You logic goes here.
     }
}

您可以从MSDN获取有关如何读/写剪贴板内容的帮助。

Answer 3

我想〜你想要一个只能接受数字的TextBox吗？

如果是，则通过SetWindowLong（）在TextBox上设置ES_NUMBER样式：

public partial class Form1 : Form
{

    public Form1()
    {
        InitializeComponent();
        this.Load += Form2_Load;
    }

    private void Form1_Load(object sender, EventArgs e)
    {
        SetNumbersOnlyTextBox(this.textBox1);
    }

    public const int GWL_STYLE = (-16);
    public const int ES_NUMBER = 0x2000;

    [System.Runtime.InteropServices.DllImport("user32.dll", SetLastError = true)]
    static extern int GetWindowLong(IntPtr hWnd, int nIndex);

    [System.Runtime.InteropServices.DllImport("user32.dll")]
    static extern int SetWindowLong(IntPtr hWnd, int nIndex, int dwNewLong);

    public void SetNumbersOnlyTextBox(TextBox TB)
    {
        SetWindowLong(TB.Handle, GWL_STYLE, GetWindowLong(TB.Handle, GWL_STYLE) | ES_NUMBER);
    }

}

或者，您可以从TextBox继承并在CreateParams（）中设置ES_NUMBER：

public class IntegerTextBox : TextBox
{

    private const int ES_NUMBER = 0x2000;

    protected override CreateParams CreateParams
    {
        get
        {
            CreateParams cp = base.CreateParams;
            cp.Style = cp.Style | ES_NUMBER;
            return cp;
        }
    }

}

Answer 4

如果你真的只想允许只有数字的贴片，那么从TextBox继承并捕获WM_PASTE，在需要时禁止显示消息：

public class DigitsOnlyOnPasteTextBox : TextBox
{

    private const int WM_PASTE = 0x302;

    protected override void WndProc(ref Message m)
    {
        if (m.Msg == WM_PASTE && Clipboard.ContainsText())
        {
            int i;
            string txt = Clipboard.GetText();
            foreach(char c in txt)
            {
                if (!char.IsNumber(c))
                {
                    return;// suppress default behavior
                }
            }
        }
        base.WndProc(ref m); // allow normal processing of the message
    }

}

粘贴到文本框中时，C＃检查剪贴板中的字符

4 个答案: