c# - 如何在if语句中说“或”

Question

private void caseTextBox_TextChanged(object sender, EventArgs e)
        {
            var CTcase = caseTextBox.Text;
            caseTextBox.CharacterCasing = CharacterCasing.Upper;

            if (CTcase == "THRUHOLE") 
            {
                displayLabel3.Text = "0";
            }
            else if (CTcase == "EIAA")
            {
                displayLabel3.Text = "1";
            }
            else if (CTcase == "EIAB")
            {
                displayLabel3.Text = "2";
            }
            else if (CTcase == "EIAC")
            {
                displayLabel3.Text = "3";
            }
            else if (CTcase == "EIAD")
            {
                displayLabel3.Text = "4";
            }
            else
            {
                displayLabel3.Text = "error";
            }
        }

在每个语句中，有3个值可以等于显示正确的数字。但是我不想编写15个 if / else语句来使其工作。我尝试使用 ||， |， &和 &&。但我不断收到错误消息


  运算符不能应用于类型为'bool'和'string'的操作数

 private void caseTextBox_TextChanged(object sender, EventArgs e)
        {
            var CTcase = caseTextBox.Text;
            caseTextBox.CharacterCasing = CharacterCasing.Upper;

            if (CTcase == "THRUHOLE") 
            {
                displayLabel3.Text = "0";
            }
            else if (CTcase == "EIAA" || "1206")
            {
                displayLabel3.Text = "1";
            }

Answer 1

例如：

if (CTcase == "THRUHOLE" || CTcase == "something else") 
        {
            displayLabel3.Text = "0";
        }

但是-对于这种情况-使用枚举。它更具可读性！
https://msdn.microsoft.com/pl-pl/library/sbbt4032.aspx