How can I determine the currently running assembly?

You can determine the currently running assembly by using the Assembly class:

C#:

System.Reflection.Assembly asm = System.Reflection.Assembly.GetExecutingAssembly();
MessageBox.Show("The currently running assembly is: " + asm.Location);

VB .NET:

Dim asm As System.Reflection.Assembly = System.Reflection.Assembly.GetExecutingAssembly()
MessageBox.Show("The currently running assembly is: " & asm.Location)

You can determine the starting executable as follows:

C#:

System.Reflection.Assembly asm = System.Reflection.Assembly.GetEntryAssembly();
MessageBox.Show("The starting assembly is: " + asm.Location);

VB .NET:

Dim asm As System.Reflection.Assembly = System.Reflection.Assembly.GetEntryAssembly()
MessageBox.Show("The starting assembly is: " & asm.Location)

You can determine the calling executable as follows:

C#:

System.Reflection.Assembly asm = System.Reflection.Assembly.GetCallingAssembly();
MessageBox.Show("The calling assembly is: " + asm.Location);

VB .NET:

Dim asm As System.Reflection.Assembly = System.Reflection.Assembly.GetCallingAssembly()
MessageBox.Show("The calling assembly is: " + asm.Location)