Objects added to a BindingSource’s list must all be of the same type

Problem

When you’re binding a control to a list of objects by adding a BindingList to a BindingSource, you get the following exception:

System.InvalidOperationException: Objects added to a BindingSource’s list must all be of the same type.

Here’s the code causing this:

BindingList<Movie> movies = new BindingList<Movie>()
{
	new Movie()
	{
		Name = "Pulp Fiction",
		MPAARating = MPAARating.R

	},
	new Movie()
	{
		Name = "The Dark Knight",
		MPAARating = MPAARating.PG13
	}
};
this.MovieCollectionBindingSource.Add(movies);
Code language: C# (cs)

Solution

Instead of adding the BindingList to the BindingSource with Add(), set BindingSource.DataSource to the BindingList. Here’s an example:

BindingList<Movie> movies = new BindingList<Movie>()
{
	new Movie()
	{
		Name = "Pulp Fiction",
		MPAARating = MPAARating.R

	},
	new Movie()
	{
		Name = "The Dark Knight",
		MPAARating = MPAARating.PG13
	}
};
this.MovieCollectionBindingSource.DataSource = movies;
Code language: C# (cs)