C# – Setting focus to a button from text box


I have a few text boxes and buttons on my form.

Lets say txtBox1 is next to btnSubmit1,
txtBox2 is next to btnSubmit2,
txtBox3 is next to btnSubmit3.

How can I set the focus on btnSubmit3 when the user starts to type something in txtBox3.
Meaning….. if a user type in a text box the program will know what button to fire when the user press the enter key.

Best Solution

If you use a panel, you should be able to set a defaultbutton. I´m not sure if it´s an win forms application or a web forms application, but this is how you should do it with web forms:

<asp:Panel id="panel1" runat="server" DefaultButton="Button1">
   <asp:TextBox id="textbox1" runat="server" />
   <asp:Button id="Button1" runat="server" Text="Button 1" />

<asp:Panel id="panel2" runat="server" DefaultButton="Button2">
   <asp:TextBox id="textbox2" runat="server" />
   <asp:Button id="Button2" runat="server" Text="Button 2" />

<asp:Panel id="panel3" runat="server" DefaultButton="Button3">
   <asp:TextBox id="textbox3" runat="server" />
   <asp:Button id="Button3" runat="server" Text="Button 3" />