Setting Trust
If you change the preceding code to this:
System.Windows.Forms.MessageBox.Show("Hello " +
this.Application.User.LoginName);and then try to run the code, you'll get a security exception. Accessing the user's login name requires full trust, but accessing the username only requires minimal trust. To work around this problem while you are developing a template:
Open the template in Design mode and click Tools → Form Options → Security and Trust.
Deselect "Automatically determine the security level," and select the Full Trust option, as shown in Figure 10-23.

Figure 10-23. Setting trust for a form
Once you have finished developing the form, sign it with a digital certificate that will be trusted by your users. Most organizations control who has trusted certificates so that only forms that have passed testing are signed and deployed.
Templates require trust to access resources outside of the current form—for example, saving a form through code requires trust. You can avoid some of those issues by saving only through the built-in InfoPath controls.
Getting Values from Controls
Use the XPathNavigator class to get and set values from controls on the form. For example, the following code gets the value in a text box named field1 and copies it to a text box named field2:
public void CTRL6_5_Clicked(object sender, ClickedEventArgs e) { // Get field 1 XPathNavigator field1 = this.MainDataSource.CreateNavigator( ...