Nrthugu

I would like to create an entire row of ComboBoxes in a DataGrid. I have made some progress with the following:

// Declare it

private DataGridComboBoxColumn CreateCustomComboBoxDataSouce(string ColumnName) 

{

    string data = { "Date", "LEInt", "String" };

    DataGridComboBoxColumn dgCmbCol = new DataGridComboBoxColumn();

    dgCmbCol.Header = ColumnName;

    dgCmbCol.ItemsSource = data;

    return dgCmbCol;

}



// Later somewhere you can add this to create 20 columns:

for (int i = 0; i < 20; i++)

{

  DataGridComboBoxColumn newColumn = CreateCustomComboBoxDataSouce("Column-" +i);

}

// Sadly nothing is shown unless you manually specify a new row and an

// extra column as done here below, but then you get an extra column.

DataTable table = new DataTable();

table.Columns.Add("|", typeof(string));

table.Rows.Add("");

DataGridCombo.DataContext = table;

The XAML is kept to a minimum:

<DataGrid x:Name="DataGridCombo" ItemsSource="{Binding}"   Margin="0,0,0,0" />

Is there a way to set the default SelectedValue of each ComboBox? Within my for loop I do have access to the desired setting. Also, is there a way to git it to show without adding the extra column? This DataGrid is being lined up with another DataGrid that won't have that extra column.

Is there a way to set the default SelectedValue of each ComboBox?

Add a DataColumn to the DataTable per DataGridComboBoxColumn, and then set the value of the column for each row to the desired selected value:

const int n = 20;

DataTable table = new DataTable();

for (int i = 0; i<n; i++)

{

    string columnName = "Column-" + i;

    DataGridCombo.Columns.Add(CreateCustomComboBoxDataSouce(columnName));

    table.Columns.Add(columnName, typeof(string));

}

table.Rows.Add(new object[n]);

//select some values...

table.Rows[0][1] = "LEInt";

table.Rows[0][5] = "String";

DataGridCombo.DataContext = table;

Also, is there a way to git it to show without adding the extra column?

Set the HorizontalAlignment property to Left to prevent the DataGrid from stretching horizontally:

<DataGrid x:Name="DataGridCombo" ItemsSource="{Binding}" HorizontalAlignment="Left" />

After a lot of working around the issue, I eventually came to the conclusion that what I was trying to do was either not possible, or unreasonable. I changed to using a StackPanel with horizontal orientation. Here are the relevant snippets:

//XAML Layout

<StackPanel Orientation="Horizontal" VerticalAlignment="Top" Name="ComboBoxPanel"  Grid.Row="1"  Margin="0,0,0,0"  HorizontalAlignment="Left" />



//Function to create new box and set options

private ComboBox CreateComboBox(string ColumnName, string selectedItem, int width)

{

    string data = { "Date", "LEInt", "String" };



    ComboBox dgCmbCol = new ComboBox();

    dgCmbCol.ItemsSource = data;

    dgCmbCol.Name = ColumnName;

    dgCmbCol.Width = width;

    dgCmbCol.SelectedItem = selectedItem;

    dgCmbCol.SelectionChanged += DataTypeSelectionChanged;

    return dgCmbCol;

}



// This reads a JSON file and uses it's options to set the width of all the columns

// for the DataGrid and matches the ComboBoxes to it so they all line up

dynamic TableData = JsonConvert.DeserializeObject(Config.DataLayoutDefinition);

ComboBoxPanel.Children.Clear(); //Since this is run on user interaction, clear old contents.



for (int i = 0; i <  DataGridView.Columns.Count; i++)

{

    int width = TableData.data[i].ColumnWidth;

    if (TableData.data[i].DataType == "String")

    {

        width = 125;

    }

    else if (TableData.data[i].DataType == "Date")

    {

        width = 150;

    }

    else if (TableData.data[i].DataType == "LEInt")

    {

        width = 80;

    }

    else

    {

        width = 100;

    }

ComboBoxPanel.Children.Add(CreateComboBox(TableData.data[i].Column.ToString(), TableData.data[i].DataType.ToString(), width));

    DataGridView.Columns[i].Width = width;



}