HashTable problem-Pls guide

Hello Everybody:
I have created a multiclient server application. I am storing the client information and the thread hashcode in a hashtable. I want to send the information back to the client from the server by selecting the thread hashcode from the hashtable and sending the information to the same client.. THe code I have developed is as follows:


try
{


int key = System.Int32.Parse(txtThreadCode.Text);
if(threadhashtable.ContainsKey(key))

{

Object objData = txtDataRx.Text;
byte[] byData = System.Text.Encoding.ASCII.GetBytes(objData.ToString ());


m_socWorker.Send (byData);
}
}
catch(SocketException se)
{
MessageBox.Show (se.Message );
}

When I put the threadhashtable variable "key" in the Watch window . The error which I got was

key error: identifier 'key' out of scope

What should I do to rectify this error. Pls guide..

Thanks,

Rahil