Link To Another Form

I have a form called FrmPracDetails, which has details of practices and each practice has a unique prac_no populated on the form in the text box called TxtPracNo.Now, I have another form called FrmPayHistory. This form has a datagrid called DgvPayHistory, which is loaded with all the payment history of all practices. It has also a field called prac_no and stores the unique prac_no. What I want to do is, when a user is in FrmPracDetails, lets say prac_no 1155, then you open the FrmPayHistory. Only the payment history of that respective prac_no should be seen. Presently, it brings all the practices and their payment history. I have added a textbox (TextBox1) in the FrmPayHistory which links and displays the prac_no from FrmPracDetails with the following code; [code]