WPF DataGrid 将单元格绑定到具有动态列的数据模型

Question

I've got a data model that can be considered as a table with dynamic columns and rows.

The model exposes a collection that defines the columns that currently exist. Each column is an object (a model) itself. The model also exposes a collection containing the rows. Also each row is a model representing the row.

Each row exposes a collection that contains the column values. Each column "value" is a model too.

MyModel
    - Columns (list of MyModelColumn)
    - Rows (list of MyModelRow)
    
MyModelColumn
    - Header (string)
    - ...

MyModelRow
    - Values (list of MyModelCell)
    - ...
    
MyModelCell
    - CalculatedValue
    - DisplayValue
    - Color
    - ...

What I would like to achieve is:

• A DataGrid that has columns dynamically created, corresponding to MyModel.Columns
• Each cell in the DataGrid must be able to bind to properties of the corresponding MyModelCell .
• Each DataGrid column is a DataGridTemplateColumn .

It seems to be not too hard, but I tried several different approaches and still can't get it done.

I managed creating DataGrid columns dynamically (from codebehind).

The DataGrid 's own behavior makes each cell in a DataGridTemplateColumn have its DataContext set to the "data item" that belongs to the whole row. In this case, the DataContext of each DataGrid cell is a MyModelRow instance.

The DataTemplate for the DataGrid cell knows about the MyModelRow , and can bind to properties on that class directly, but that's not what I want. I want to bind to the corresponding MyModelCell that belongs to the row/column. From within the CellTemplate (and CellEditingTemplate) you can never determine in what column the cell is, and so you don't know which MyModelCell (from MyModelRow.Values ) you have to access to read a property of the MyModelCell .

The main problem is: how to connect each cell in the DataGrid to the MyModelCell it belongs to?

My data model classes I'm talking about are viewmodels, and the problem is mainly UI related. So, using codebehind is fine, and maybe even unavoidable.

Answer 1

The main problem is: how to connect each cell in the DataGrid to the MyModelCell it belongs to?

Since the DataContext of a DataGridRow is always the current item of type T in the IEnumerable<T> sequence that the DataGrid 's ItemsSource property is set or bound to, you will have to include the index of the cell in the binding paths in the CellTemplate and CellEditingTemplate , eg:

Binding="{Binding Values[0].CalculatedValue}"

...for the first column.

This means that you will have to (preferably programmatically) create a separate template for each column where you replace [0] in the binding path(s) with the index of that column's cell.