.Net常用技巧_TextBox文本框限制输入的内容

   private void txtSize_KeyPress(object sender, KeyPressEventArgs e)
        {
            if (e.KeyChar != 8 && e.KeyChar != 13 && !char.IsDigit(e.KeyChar) && e.KeyChar != 46)
            {
                MessageBox.Show("请输入数字");
                e.Handled = true;
            }
        }

  private void txtChar_KeyPress(object sender, KeyPressEventArgs e)
        {
            if (e.KeyChar != 8 && e.KeyChar != 13 && (!char.IsUpper(e.KeyChar) && !char.IsLower(e.KeyChar)))
                {
                    MessageBox.Show("请输入字母。");
                    e.Handled = true;
                }
        }

   private void txtClassCode_KeyPress(object sender, KeyPressEventArgs e)
        {
            if (frmStart != "IsEdit")
            {
                if (e.KeyChar != 8 && e.KeyChar != 13 && (!char.IsUpper(e.KeyChar) && !char.IsLower(e.KeyChar)))
                {
                    MessageBox.Show("请输入字母。");
                    e.Handled = true;
                }

                if (e.KeyChar != 8 && e.KeyChar != 13 && (txtClassCode.Text.Length - txtClassCode.SelectedText.Length > 0))
                {
                    MessageBox.Show("只允许输入一位字母。");
                    e.Handled = true;
                }
            }
        }

  private void SetTextLen()
        {
            this.txtClassCode.MaxLength = 30;
            this.txtClassName.MaxLength = 100;
            this.txtNnemonicCode.MaxLength = 128;
            this.txtSpellCode.MaxLength = 255;
            this.txtDescription.MaxLength = 255;
            this.txtRemark.MaxLength = 255;
        }