如何使用While和Do While在标签中显示前100个偶数？ C＃

Question

Actually i have a button to display the first 100 even numbers using For

    int a = 100;
        int res = 0;
        int i;
        string npares = "";
        for (i = 0; i <= a; i++)
        {
            if (i % 2 == 0)
            {
                res = res + i;
                if (i < a)
                    npares += i + ",";
                else
                    npares += i;
            }


        }
        LBLstatus.MaximumSize = new Size(200, 0);
        LBLstatus.Text = npares;

But i need to make the same with more two buttons using While and Do While , how i can make this ?

EDIT >>>>>>

Using while i got this way :

int a = 100;
        int i = 0;
        string npares = "";
        int res = 0;

        while (i <= a)
        {
            i++;
            if

                (i % 2 == 0)
            {
                res = res + i;
                if (i < a)
                    npares += i + ",";
                else
                    npares += i;
            }
            LBLstatus.Text = npares;

Answer 1

(This answer shows the relationship between constructs, but does not otherwise attempt to provide a solution.)

---

The construct

for (init;cond;post)
{
    body;
}

can be generally rewritten as / considered equivalent to

init;
while (cond) {
    body;
    post;
}

On the other hand a do-while has no analogous simple for form, because it delays evaluation of cond until after the body has been executed once, but it can be written as

for (init;;post) {
    body;
    if (!cond) break;
}

Answer 2

Using Take

List<int> ints;

List<int> positiveInts = ints.Where(i => i % 2 == 0).Take(100).ToList();

Using Aggregate

List<int> ints;

string positiveInts = ints.Where(i => i % 2 == 0).Take(100).Select(i => i.ToString()).Aggregate((a,b) => b += String.IsNullOrEmpty(b) ? a : "," + a);