WinForm中Label文本不显示求助：数组批量赋值无效

问题根源 #

你当前代码里的seq_Left、seq_Right这类数组，存储的是Label控件Text属性的值副本，而非控件本身的引用。当你修改数组元素时，只是改变了数组里的字符串内容，并没有同步更新到Label控件的Text属性，所以界面上看不到任何变化。

方案1：存储控件引用（推荐） #

把字符串数组改成对应控件类型的数组，直接操作控件的Text属性，既简洁又能实时更新界面：

private void SetUpGame()
{
    // 存储Label/TextBox控件的引用，而非Text属性的值
    Label[] seq_Left = { lblNum1Left, lblNum2Left, lblNum3Left, lblNum4Left, lblNum5Left };
    Label[] seq_Right = { lblNum1Right, lblNum2Right, lblNum3Right, lblNum4Right, lblNum5Right };
    Label[] seq_Symbol = { lblSymbol1, lblSymbol2, lblSymbol3, lblSymbol4, lblSymbol5 };
    TextBox[] seq_Answer = { txtAnswer1, txtAnswer2, txtAnswer3, txtAnswer4, txtAnswer5 };

    for (int i = 0; i < 5; i++)
    {
        int numA = rnd.Next(10, 20);
        int numB = rnd.Next(0, 9);

        seq_Answer[i].Text = "";

        switch (Maths[rnd.Next(0, Maths.Length)])
        {
            case "Add":
                total[i] = numA + numB;
                seq_Symbol[i].Text = "+";
                break;

            case "Subtract":
                total[i] = numA - numB;
                seq_Symbol[i].Text = "-";
                break;

            case "Multiply":
                total[i] = numA * numB;
                seq_Symbol[i].Text = "x";
                break;
        }

        seq_Left[i].Text = numA.ToString();
        seq_Right[i].Text = numB.ToString();
    }
}

方案2：修改数组后同步赋值回控件 #

如果不想调整数组类型，也可以在循环结束后，把数组中的字符串值重新赋值给对应控件的Text属性，但这种方式会增加冗余代码，不如方案1高效：

private void SetUpGame()
{
    string[] seq_Left = new string[5];
    string[] seq_Right = new string[5];
    string[] seq_Symbol = new string[5];
    string[] seq_Answer = new string[5];

    for (int i = 0; i < 5; i++)
    {
        int numA = rnd.Next(10, 20);
        int numB = rnd.Next(0, 9);

        seq_Answer[i] = "";

        switch (Maths[rnd.Next(0, Maths.Length)])
        {
            case "Add":
                total[i] = numA + numB;
                seq_Symbol[i] = "+";
                break;

            case "Subtract":
                total[i] = numA - numB;
                seq_Symbol[i] = "-";
                break;

            case "Multiply":
                total[i] = numA * numB;
                seq_Symbol[i] = "x";
                break;
        }

        seq_Left[i] = numA.ToString();
        seq_Right[i] = numB.ToString();
    }

    // 将数组值同步回控件
    lblNum1Left.Text = seq_Left[0];
    lblNum2Left.Text = seq_Left[1];
    lblNum3Left.Text = seq_Left[2];
    lblNum4Left.Text = seq_Left[3];
    lblNum5Left.Text = seq_Left[4];

    lblNum1Right.Text = seq_Right[0];
    lblNum2Right.Text = seq_Right[1];
    lblNum3Right.Text = seq_Right[2];
    lblNum4Right.Text = seq_Right[3];
    lblNum5Right.Text = seq_Right[4];

    lblSymbol1.Text = seq_Symbol[0];
    lblSymbol2.Text = seq_Symbol[1];
    lblSymbol3.Text = seq_Symbol[2];
    lblSymbol4.Text = seq_Symbol[3];
    lblSymbol5.Text = seq_Symbol[4];

    txtAnswer1.Text = seq_Answer[0];
    txtAnswer2.Text = seq_Answer[1];
    txtAnswer3.Text = seq_Answer[2];
    txtAnswer4.Text = seq_Answer[3];
    txtAnswer5.Text = seq_Answer[4];
}

内容的提问来源于stack exchange，提问作者Ahmet