Has more than one entry point defined error

Question

I have the following code:

namespace WpfApplication2
{
    /// 

    /// Interaction logic for MainWindow.xaml
    /// 
    public p         


        

Answer 1

You have two primary options to implement on start activities:

Event handlers

File App.xaml

<Application x:Class="CSharpWPF.App"
             xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
             xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
             StartupUri="MainWindow.xaml"
             Startup="Application_Startup">

Define Startup="Application_Startup" and handle in file App.xaml.cs:

    private void Application_Startup(object sender, StartupEventArgs e)
    {
        // On start stuff here
    }

Override method

File App.xaml.cs

public partial class App : Application
{
    protected override void OnStartup(StartupEventArgs e)
    {
        // On start stuff here
        base.OnStartup(e);

        // Or here, where you find it more appropriate
    }
}

Answer 2

In order to solve this error, don't change the name of the .cs file when creating new code.

If you want a new name for your .cs file then you have to delete everything in the folder where your project is i.e., the fragments of files (bin, obj folders, etc.).