Hex to Ascii Conversion in C#

try
{
int n =0;
string temp;
string temp2 = "";
for(int i = 0; i {
temp = txtKeyA.Text.Substring(i,2);
n = Convert.ToInt32(temp, 16);
//To convert it to a character, simply cast the integer to char
temp2 = temp2 + ((char)n).ToString();
}
txtKeyA.Text = temp2;
this.btnToHex.Enabled = true;
this.btnToAscii.Enabled = false;
}
catch(Exception eE)
{
// MessageBox.Show(eE.ToString());
MessageBox.Show("Failed to convert!!! Please check your input format!");
}