bindingsource not filling in custom list.

[MarcG]

I am using a bindingsource as the datasource to a datagridview. In the
bindingsource properties, I set DataSource to "TaskSchedule", a class derived
from List<ScheduleItem>. I perform all schedule operations
(add/delete/modify) via BindingSource's Item, Add, and Remove methods. The
app works "properly" but BindingSource.List does not give me a TaskSchedule
object back. In fact, I can find nothing that looks like a TaskSchedule from
the BindingList.

If I change BindingList.Datasource to ScheduleItem, the application works
the same way.

Why is BindingSource not creating a TaskSchedule, or giving me a way to give
it a TaskSchedule object to use as a datasource? (I want to continue to set
the DataSource type at design time so that the DataGridView will generate the
columns for me)

Thx
Marc

 

[Bob Powell [MVP]]

Rather than use a List<t> use a BindingList<t> for your objects. This
integrates better with the BindingSource.


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[Linda Liu[MSFT]]

Hi Marc,

The app works "properly" but BindingSource.List does not give me a

TaskSchedule object back.

I performed a test based on your description but didn't reproduce the
problem on my side. The following is the my test code.

BindingSource bs = new BindingSource();
private void Form1_Load(object sender, EventArgs e)
{
TaskSchedule datasource = new TaskSchedule();
bs.DataSource = datasource;
object list = bs.List; // the variable list is of type
"TaskSchedule"
}

public class ScheduleItem
{
string name;
public string Name
{
get { return name; }
set { name = value; }
}
}

I want to continue to set the DataSource type at design time so that the

DataGridView will generate the columns for me

Based on my understanding, you'd like to set the DataSource property of a
DataGridView to the TaskSchedule at design time. If I'm off base, please
feel free to let me know.

To do this, you need to inherit the TaskSchedule class from Component and
implement the IListSource interface for the TaskSchedule class. The
following is a sample.

public class TaskSchedule : Component, IListSource
{
System.Collections.IList IListSource.GetList()
{
List<ScheduleItem> ble = new List<ScheduleItem>();
return ble;
}
bool IListSource.ContainsListCollection
{
get { return false; }
}
}
public class ScheduleItem
{
string name;
public string Name
{
get { return name; }
set { name = value; }
}
}

Hope this helps.
If you have any question, please feel free to let me know.

Sincerely,
Linda Liu
Microsoft Online Community Support

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[MarcG]

Linda,

That was it of course. It just seems a little odd to set the type at design
time so that you can easily customize the columns in the datagridview and
then stick the object in at run time.

Bill,

I agree that using BindingSource<T> creates a "better fit", but the
underlying object might have some other inheritance path.

Thx to both,
Marc