R – Using Mode=TwoWay and AutogenerateColumns=True in Silverlight 3 DataGrid

autogeneratecolumnbindingdatagridsilverlight-3.0

My List<BusinessObject> has some public properties that I want to bind to columns in a DataGrid. Unfortunately, the names of the public properties are not good and I may not even know what they are until runtime. For this reason, I set AutoGenerateColumns=True and interecept each DataGridAutoGeneratingColumnEvent so I can inspect what it is and either cancel it, hide it, or name the header something else.

It works great but I cannot figure out how to set the Mode=TwoWay so that my INotifyPropertyChanged events get fired once all the columns are generated and somebody edits a cell.

Bonus question:
On navigating up and down the rows of the grid, does the grid's datacontext automatically get set with that row's BusinessObject?

Best Answer

Thanks to this post, I learned that the binding happens on DataGridTextColumn. So the way to set the Mode at runtime is:

1    private void DataGrid1_AutoGeneratingColumn(object sender, DataGridAutoGeneratingColumnEventArgs e)
2    {
3        DataGridTextColumn tc = (DataGridTextColumn)e.Column;
4        tc.Header = "Custom Header";
5        tc.Binding.Mode = BindingMode.TwoWay;
6    }

Now that I have TwoWay binding, I have to figure out how changes make it back to my BusinessObject.

Related Solutions

C# – How to manually add data to a DataGrid in Silverlight

Assume you have a class or some other container that you want to bind information to, you can do the following.

DataGridTextColumn product = new DataGridTextColumn();
                product.Binding = new System.Windows.Data.Binding("Product");
                product.Header = "Product";

                DataGridTextColumn date = new DataGridTextColumn();
                date.Binding = new System.Windows.Data.Binding("Date");
                date.Header = "Date";

                DataGridTextColumn version = new DataGridTextColumn();
                version.Binding = new System.Windows.Data.Binding("FileVersion");
                version.Header = "Version";

                DataGridTextColumn timestamp = new DataGridTextColumn();
                timestamp.Header = "TimeStamp";
                timestamp.Binding = new System.Windows.Data.Binding("TimeStamp");

                DataGridTextColumn user = new DataGridTextColumn();
                user.Header = "User";
                user.Binding = new System.Windows.Data.Binding("User");

                rpdata.Columns.Add(product);
                rpdata.Columns.Add(date);
                rpdata.Columns.Add(version);
                rpdata.Columns.Add(timestamp);
                rpdata.Columns.Add(user);

Now just set your itemsource of the datagrid to the collection of items you have.

This allows you to set the header you want to display, and it also binds the information to variables in the container, thus it displays the information of only the columns you add.

R – SilverLight – MVVM binding viewmodel property to datagrid column

~~Assuming your ViewModel is assigned as the LayoutRoot's DataContext this should work:-~~

~~IsChecked="{Binding DataContext.vmProperty, ElementName=LayoutRoot}"~~

Of course this doesn't work, ultimately a template is replicated and therefore "LayoutRoot" does not exist in the namescope where the binding is actually used.

The simplest solution since this is a ViewModel is to change the model. Expose the required value on the objects available in the dgSource or expose a Parent property that navigates back to the ViewModel.

Best Answer

Related Solutions

C# – How to manually add data to a DataGrid in Silverlight

R – SilverLight – MVVM binding viewmodel property to datagrid column

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