Vb.net 不区分大小写

我试图使用户输入的字母a、b、c、d不敏感。尝试使用UCase，但不起作用（不确定是否使用错误）。我在Visual Studio 2012中使用VB。任何引用都很好。

您可以使用方法：

String.Compare（String-strA、String-strB、Boolean-ignoreCase）

使用

true

传递

ignoreCase

参数将执行不区分大小写的比较

If TextBox2.Text = "a" AndAlso TextBox21.Text = "a" Then
        'MessageBox.Show("A")
        totCorrect = totCorrect + corAns
    ElseIf TextBox2.Text = "b" AndAlso TextBox21.Text = "b" Then
        'MessageBox.Show("B")
        totCorrect = totCorrect + corAns
    ElseIf TextBox2.Text = "c" AndAlso TextBox21.Text = "c" Then
        'MessageBox.Show("C")
        totCorrect = totCorrect + corAns
    ElseIf TextBox2.Text = "d" AndAlso TextBox21.Text = "d" Then
        'MessageBox.Show("D")
        totCorrect = totCorrect + corAns
    Else
        totWrong = totWrong + wrgAns
        Label13.Visible = True
    End If

另一个想法是使用or将输入大写或小写

---

根据VB.NET中的MSDN，只需向文件中添加1行代码即可使用：

选项比较文本

如果将上述行添加到代码开头，则说明CLR从默认值（

选项Compare Binary

）切换到不区分大小写的比较，作为

=

运算符的新默认值

---

我不知道是否有其他选择。

请看：谢谢，这非常有用

If String.Compare(TextBox2.Text, "a", true) = 0 AndAlso String.Compare(TextBox21.Text, "a", true) = 0 Then
        'MessageBox.Show("A")
        totCorrect = totCorrect + corAns
    ElseIf String.Compare(TextBox2.Text, "b", true) = 0 AndAlso String.Compare(TextBox21.Text, "b", true) = 0 Then
        'MessageBox.Show("B")
        totCorrect = totCorrect + corAns
    ElseIf String.Compare(TextBox2.Text, "c", true) = 0 AndAlso String.Compare(TextBox21.Text, "c", true) = 0 Then
        'MessageBox.Show("C")
        totCorrect = totCorrect + corAns
    ElseIf String.Compare(TextBox2.Text, "d", true) = 0 AndAlso String.Compare(TextBox21.Text, "d", true) = 0 Then
        'MessageBox.Show("D")
        totCorrect = totCorrect + corAns
    Else
        totWrong = totWrong + wrgAns
        Label13.Visible = True
    End If

If TextBox2.Text.ToUpper() = "A" AndAlso TextBox21.Text.ToUpper() = "A" Then
            'MessageBox.Show("A")
            totCorrect = totCorrect + corAns
        ElseIf TextBox2.Text.ToUpper() = "B" AndAlso TextBox21.Text.ToUpper() = "B" Then
            'MessageBox.Show("B")
            totCorrect = totCorrect + corAns
        ElseIf TextBox2.Text.ToUpper() = "C" AndAlso TextBox21.Text.ToUpper() = "C" Then
            'MessageBox.Show("C")
            totCorrect = totCorrect + corAns
        ElseIf TextBox2.Text.ToUpper() = "D" AndAlso TextBox21.Text.ToUpper() = "D" Then
            'MessageBox.Show("D")
            totCorrect = totCorrect + corAns
        Else
            totWrong = totWrong + wrgAns
            Label13.Visible = True
        End If