Looping in textBox

That it`s work just fine ... thanks a lot !!!

try this:
public partial class Form1 : Form
{
int mIndex1, mIndex2,uIndex;
string cm = " , ";
public Form1()
{
InitializeComponent();
}
private void Form1_Load(object sender, EventArgs e)
{
mIndex1 = 0;
mIndex2 = 0;
uIndex = 0;
}
private void bttnRead_Click(object sender, EventArgs e)
{
uIndex = Convert.ToInt32(textBox1.Text);
textBox2.Text = (Convert.ToString(mIndex1) + cm + Convert.ToString(mIndex2));
textBox3.Text = string.Empty;
mIndex1 = 0;
mIndex2 = 0;
}
private void bttnYes_Click(object sender, EventArgs e)
{
}
private void bttnNo_Click(object sender, EventArgs e)
{
if (mIndex2 < uIndex && mIndex1 != uIndex)
{
mIndex2++;
}
else if (mIndex1 == uIndex)
{
textBox3.Text = ("Finished looping");
return;
}
else if (mIndex1 < uIndex && mIndex2 == uIndex)
{
mIndex1++;
mIndex2 = 0;
}
textBox2.Text = (Convert.ToString(mIndex1) + cm + Convert.ToString(mIndex2));
}
}

In the first text box the user will insert a number. For example 3 and this number represent the number of rows and columns. After pressing Read in the second text box I wanna make to  appear the looping for matrix eg: "It is a node between"a[1,1] and user press yes or no after that to appear a[1,2].... a[3,2] a[3,3]. If he put the number 5 to make looping until reach at a[5,5]. 
in the result will appear for eg:
1 0 1
0 1 1
1 1 1 depending on response
But the problem for me is how to make the looping in text box ...
Tx