//限制只能輸入漢字,正則表示式
  if(!Regex.IsMatch(this.txtdepartment.Text.Trim(),"[\u4e00-\u9fa5]")&& this.txtdepartment.Text.Length >= 4)
  {
       MessageBox.Show("請輸入漢字，且漢字個數不超過4個");
       txtdepartment.Text = "";
       txtdepartment.Focus();
       return;
  }
  
//只能輸入數字
   private void txtcardno_KeyPress(object sender, KeyPressEventArgs e)
    {
        if ((int)e.KeyChar >= 48 & (int)e.KeyChar <= 57 | (int)e.KeyChar == 8)
        {
            e.Handled = false;
        }
        else
        {
            MessageBox.Show("請輸入數字");
            e.Handled = true;
        }
     }
 //建立一個函式，用來呼叫判斷是否為數字
 public bool IsNumber(string text)//判斷是否為數字的函式
    {
        try
        {
            int var = Convert.ToInt32(text);
            return true;
        }
        catch
        {
            return false;
        }
    }