Question

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消息框总是说我输入的是“输入错误”，只有出现第一个“ if”的消息框，当我键入正确的名称（某物）时，它也出现在代码的第一部分：（

private void Submit_Click(object sender, EventArgs e) { if (textBox_Name.Text.Length == 0 && (textBox_Name.Text != "something" || textBox_Name.Text != "something")) { string message = "Your name is not " + textBox_Name.Text; string caption = "Error input"; MessageBoxButtons buttons = MessageBoxButtons.RetryCancel; MessageBox.Show(message, caption, buttons); textBox_Name.Clear(); else MessageBox.Show("Good job something you know your name, LOL"); }语句甚至没有被检查。

我正在验证Windows窗体应用程序中文本框的内容。

Answer 1

在我看来，就像您弄糟了if / else条件（如果我理解您要正确执行的操作）。

这是应该起作用的代码：

private void Submit_Click(object sender, EventArgs e)
{
    if (textBox_Name.Text == "OptionA" || textBox_Name.Text == "OptionB")
        MessageBox.Show("Good job, at least you know your own name, LOL");

    else 
    {
        string message = "Your name is not " + textBox_Name.Text;
        string caption = "Error input";
        MessageBoxButtons buttons = MessageBoxButtons.RetryCancel;
        MessageBox.Show(message, caption, buttons);
        textBox_Name.Clear();
    }
}

Answer 2

您的测试逻辑在括号内显得很奇怪。

if ((textBox_Name.Text.Length == 0) && ((textBox_Name.Text != "something") || (textBox_Name.Text != "something")))

以缩写形式仅显示上下文

if(( textLength == 0 && ( text != "something" || text != "something" ) ))

请注意，您的文本长度本身就是全部，然后是（x OR x）的AND。只有在文本框中有一个空字符串时，它才会返回TRUE。因为字符串长度将为零长度，而实际文本不会是“某物”。

您可能需要进行更多测试，例如...

if( string.IsNullOrWhiteSpace( textBox_Name.Text ))
{
   MessageBox.Show("You have not entered a value for the name");
   return;
}      

if( textBox_Name.Text.Equals( "something", StringComparison.CurrentCultureIgnoreCase )
{
   string message = "Your name is not " + textBox_Name.Text;
   string caption = "Error input";
   MessageBoxButtons buttons = MessageBoxButtons.RetryCancel;
   MessageBox.Show(message, caption, buttons);
   textBox_Name.Clear();
   return;
}

// else, must have had something valid other than empty or "something" regardless of case.
MessageBox.Show("Good job something you know your name, LOL");

如何解决以下代码中的错误？

2 个答案: