For 循环：变量名中包含 i

Question

SubnetConvert SubnetOctet1 = new SubnetConvert();
SubnetConvert SubnetOctet2 = new SubnetConvert();
SubnetConvert SubnetOctet3 = new SubnetConvert();
SubnetConvert SubnetOctet4 = new SubnetConvert();

    int Octet1 = int.Parse(txtOctet1.Text);
    SubnetOctet1.OctetConvert = Octet1;
    lblOctet1.Text = SubnetOctet1.SendBinary;

    int Octet2 = int.Parse(txtOctet2.Text);
    SubnetOctet2.OctetConvert = Octet2;
    lblOctet2.Text = SubnetOctet1.SendBinary;

    int Octet3 = int.Parse(txtOctet3.Text);
    SubnetOctet3.OctetConvert = Octet3;
    lblOctet3.Text = SubnetOctet1.SendBinary;

    int Octet4 = int.Parse(txtOctet4.Text);
    SubnetOctet4.OctetConvert = Octet4;
    lblOctet4.Text = SubnetOctet1.SendBinary;

是否可以将所有这些代码放入 For 循环中，就像

For (int i = 1; i <=4; i++)
{
SubnetConvert SubnetOctet[i] = new SubnetConvert();

    int Octet[i] = int.Parse(txtOctet[i].Text);
    SubnetOctet[i].OctetConvert = Octet[i];
    lblOctet[i].Text = SubnetOctet[i].SendBinary;
}

我尝试过上面的编码一样，但它不起作用，我只是将其放在那里作为我想要实现的示例

Answer 1

代码示例是不可能的 - 正如您所显示的，不支持控制数组。

更好的方法是编写一个函数来封装重复代码并传入不同的参数。

private void SetBinaryValue(string value, Label display)
{
    int Octet = int.Parse(value);
    SubnetOctet.OctetConvert = Octet;
    display.Text = SubnetOctet.SendBinary;
}

您可以像这样调用此函数：

SetBinaryValue(txtOctet1.Text, lblOctet1);
SetBinaryValue(txtOctet2.Text, lblOctet2);

请注意，使用此方法您只需要一个 SubnetConvert（您可以在函数内初始化它，也可以将其初始化为一个字段）。

Answer 2

使用 FindControl 循环遍历命名控件是完全可能的：

var subnetOctet = new SubnetConvert();

for (int i = 1; i <= 4; ++i) {
    // ID suffix as string
    var indexText = i.ToString(CultureInfo.InvariantCulture);

    // ID of TextBox and Label
    var textBoxId = "txtOctet" + indexText;
    var labelId = "lblOctet" + indexText;

    // The TextBox and the Label
    var textBox = (TextBox)FindControl(textBoxId);
    var label = (Label)FindControl(labelId);

    // Parse the value into an int
    int octet = int.Parse(textBox.Text);

    subnetOctet.OctetConvert = octet;

    // Update the TextBox's Test
    label.Text = subnetOctet.SendBinary;
}

使用此方法的一个优点是您可以动态添加更多控件，甚至可以通过编程方式添加更多控件，并且如果您跟踪您需要的子网数量，需要处理，你不必更新你的代码。

Answer 3

您还可以使用您的对象作为元素创建一个数组，然后循环遍历该数组并根据循环位置处的数组位置执行函数；

Dog pet1 = new Dog();
        Dog pet2 = new Dog();
        Dog pet3 = new Dog();
        Dog pet4 = new Dog();

        //create a list of pets and add your pets to them
        List<Dog> pets = new List<Dog>();
        pets.Add(pet1);
        pets.Add(pet2); 
        pets.Add(pet3);
        pets.Add(pet4);


        //Using a for each loop to go through each element in the array and execute identical actions on each 
        //element
        foreach (Dog pet in pets)
        {
            pet.SetName("Fido");
        }

        //or create a for each loop that will allow you to know the position 
        //you are currenly at in the arry as the integer of i increments in the loop
        for (int i = 0; i <= pets.Count; i++)
        {
            pets[i].SetName("Fido");
        }

理想情况下，您想要做的是创建一个对象并通过另一个循环将该对象的多个实例插入到列表中，然后使用 foreach 或 for 循环访问列表的元素以操作单个实例。

Dog dog = new Dog();

        //create a list of pets and add your pets to them
        List<Dog> pets = new List<Dog>();

        for (int i = 0; i <= 5; i++)
        {
            pets.Add(dog);
        }

        //Using a for each loop to go through each element in the array and execute identical actions on each 
        //element
        foreach (Dog pet in pets)
        {
            pet.SetName("Fido");
        }