Convert int to string In For loop condition

It might help you,

CSharpNumericToString[^]

:)

Despite the probability that this is a homework question...

StringBuilder builder = new StringBuilder();
foreach(int i in collection)
{
    builder.AppendFormat("{0}", i);
}

Use ToString() to convert int to string

int a=10;
string b=a.ToString();

If you are trying to convert an integer to a string manually, rather than using the ToString method, then this is homework! So, no code.

But, it isn't difficult. Although a for loop is not the most ideal structure, it can be done.
1) Create a char array to hold the output.
2) Create your for loop, so that it runs from the right hand side of the array, to the left:

for (int i = myArray.Length - 1; i >= 0; i--)

(I lied about the no code)
3) Inside the loop, take the last digit of you integer (using the modulus operator), convert it to a printable digit and insert it in the array at the current position.
4) Remove the digit from the input, by using the divide operator.
5) When the loop ends, you will have the integer converted into a char array. Convert it to a string, using the appropriate string constructor.
Your string now contains the converted integer, fully padded with '0's.
You may wish to remove leading zeros, but that is up to you...