如何使TextBox只接受字母字符

您可以使用以下代码段：

private void textBox1_TextChanged(object sender, EventArgs e)
{
    if (!System.Text.RegularExpressions.Regex.IsMatch(textBox1.Text, "^[a-zA-Z ]"))
    {
        MessageBox.Show("This textbox accepts only alphabetical characters");
        textBox1.Text.Remove(textBox1.Text.Length - 1);
    }
}

您可以尝试处理文本框的KeyPress事件

void textBox1_KeyPress(object sender, KeyPressEventArgs e)
{
    e.Handled = !(char.IsLetter(e.KeyChar) || e.KeyChar == (char)Keys.Back);
}

此外，如果你想删除一些文本，请允许退格，这对你的来说应该很好

编辑

上面的代码不适用于粘贴到字段中，我相信你必须使用TextChanged事件，但这会有点复杂，因为你必须删除不正确的字符或突出显示它，并放置光标让用户进行更正，或者你可以在用户输入完整的文本和标签后进行验证。

private void textbox1_KeyDown_1(object sender, KeyEventArgs e)
{
    if (e.Key >= Key.A && e.Key <= Key.Z)
    {
    }
    else
    {
       e.Handled = true;
    }
}

最简单的方法是处理TextChangedEvent并检查键入的内容：

string oldText = string.Empty;
    private void textBox2_TextChanged(object sender, EventArgs e)
    {
        if (textBox2.Text.All(chr => char.IsLetter(chr)))
        {
            oldText = textBox2.Text;
            textBox2.Text = oldText;
            textBox2.BackColor = System.Drawing.Color.White;
            textBox2.ForeColor = System.Drawing.Color.Black;
        }
        else
        {
            textBox2.Text = oldText;
            textBox2.BackColor = System.Drawing.Color.Red;
            textBox2.ForeColor = System.Drawing.Color.White;
        }
        textBox2.SelectionStart = textBox2.Text.Length;
    }

如果您愿意，这是一个regex免费版本。它会使文本框在输入错误时闪烁。请注意，它似乎也支持粘贴操作。

将Text_KeyPress事件中的代码写入

 private void textBox1_KeyPress(object sender, KeyPressEventArgs e)
    {
        if (!char.IsLetter(e.KeyChar))
        {
            e.Handled = true;
        }
    }

这台运行得非常好。。。

 private void manufacturerOrSupplierTextBox_KeyPress(object sender, KeyPressEventArgs e)
    {
        if (char.IsControl(e.KeyChar) || char.IsLetter(e.KeyChar))
        {
            return;
        }
        e.Handled = true;
    }

此解决方案使用正则表达式，不允许将无效字符粘贴到文本框中，并保持光标位置。

using System.Text.RegularExpressions;
int CursorWas;
string WhatItWas;
private void textBox1_Enter(object sender, EventArgs e)
    {
        WhatItWas = textBox1.Text;
    }
private void textBox1_TextChanged(object sender, EventArgs e)
    {
        if (Regex.IsMatch(textBox1.Text, "^[a-zA-Z ]*$"))
        {
            WhatItWas = textBox1.Text;
        }
        else
        {
            CursorWas = textBox1.SelectionStart == 0 ? 0 : textBox1.SelectionStart - 1;
            textBox1.Text = WhatItWas;
            textBox1.SelectionStart = CursorWas;
        }
    }

注意：textBox1_TextChanged递归调用。

        if (System.Text.RegularExpressions.Regex.IsMatch(textBox1.Text, "^[a-zA-Z]+$"))
        { 
        }
        else
        {
            textBox1.Text = textBox1.Text.Remove(textBox1.Text.Length - 1);
            MessageBox.Show("Enter only Alphabets");

        }

请尝试此

private void textBox2_KeyPress(object sender, KeyPressEventArgs e)
        {
            if (e.KeyChar >= '0' && e.KeyChar <= '9')
                e.Handled = true;
            else
                e.Handled = false;
        }

试试这个

            private void tbCustomerName_KeyPress(object sender, KeyPressEventArgs e)
    {
        e.Handled = !(char.IsLetter(e.KeyChar) || e.KeyChar == (char)Keys.Back||e.KeyChar==(char)Keys.Space);
    }

它允许空白区太

您可以尝试以下代码，在按键事件时发出警报

private void tbOwnerName_KeyPress(object sender, KeyPressEventArgs e)
    {
        //===================to accept only charactrs & space/backspace=============================================
        if (e.Handled = !(char.IsLetter(e.KeyChar) || e.KeyChar == (char)Keys.Back || e.KeyChar == (char)Keys.Space))
        {
            e.Handled = true;
            base.OnKeyPress(e);
            MessageBox.Show("enter characters only");
        }

这是我的解决方案，它按计划运行：

string errmsg = "ERROR : Wrong input";
ErrorLbl.Text = errmsg;
if (e.Handled = !(char.IsLetter(e.KeyChar) || e.KeyChar == (char)Keys.Back || e.KeyChar == (char)Keys.Space))
{
  ErrorLbl.Text = "ERROR : Wrong input";
}
else ErrorLbl.Text = string.Empty;
if (ErrorLbl.Text == errmsg)
{
  Nametxt.Text = string.Empty;
}

private void textBox1_KeyPress(object sender, KeyPressEventArgs e)
    {
      if (!char.IsControl(e.KeyChar) && !char.IsLetter(e.KeyChar) &&
         (e.KeyChar !='.'))
        { 
          e.Handled = true;
          MessageBox.Show("Only Alphabets");
        }
    }

在文本框的KeyPress事件中尝试以下代码

if (char.IsLetter(e.KeyChar) == false  & 
        Convert.ToString(e.KeyChar) != Microsoft.VisualBasic.Constants.vbBack)
            e.Handled = true

适用于我，即使不是最简单的。

private void Alpha_Click(object sender, EventArgs e)
        {
            int count = 0;
            foreach (char letter in inputTXT.Text)
            {
                if (Char.IsLetter(letter))
                {
                    count++;
                }
                else
                {
                    count = 0;
                }
            }
            if (count != inputTXT.Text.Length)
            {
                errorBox.Text = "The input text must contain only alphabetic characters";
            }
            else
            {
                errorBox.Text = "";
            }
        }

就字符限制而言，这很好，如果不是C或L ，任何关于错误消息的建议都会提示我的代码

Private Sub TXTBOX_TextChanged(sender As System.Object, e As System.EventArgs) Handles TXTBOX.TextChanged
        Dim allowed As String = "C,L"
        For Each C As Char In TXTBOX.Text
            If allowed.Contains(C) = False Then
                TXTBOX.Text = TXTBOX.Text.Remove(TXTBOX.SelectionStart - 1, 1)
                TXTBOX.Select(TXTBOX.Text.Count, 0)
            End If
        Next
      
    End Sub

试试这个。空格和快捷键工作

 if (!char.IsControl(e.KeyChar) && !char.IsLetter(e.KeyChar) && !char.IsSeparator(e.KeyChar))
        {
            e.Handled = true;
        }