Why is my DataGridTemplateColumn and RadioButton not visible in my DataGrid?

Question

Why I don't see a column with a RadioButton in the DataGrid?

<DataGrid x:Name="dg" Visibility="Visible" Margin="0,191,0,374" Width="1000" HeadersVisibility="Column" SelectionUnit="Cell" CanUserAddRows="False" AutoGenerateColumns="False" HorizontalAlignment="Left" Grid.ColumnSpan="2" Grid.RowSpan="2">
    <DataGridTemplateColumn Width="85" Header="Kurs">
        <DataGridTemplateColumn.CellTemplate>
            <DataTemplate>
                <RadioButton GroupName="DataGridChkBoxes" IsChecked="{Binding IsPresent2}" x:Name="rb" Content="rb" Width="50"/>
            </DataTemplate>
        </DataGridTemplateColumn.CellTemplate>
    </DataGridTemplateColumn>

    <DataGrid.Columns>
        <DataGridTextColumn Binding="{Binding Nazwa}" Header="Nazwa" Width="300" IsReadOnly="True"/>
        <DataGridTextColumn Binding="{Binding KursZdarzenia}" Header="Kurs" IsReadOnly="True"/>
    </DataGrid.Columns>
</DataGrid>

Answer 1

Your DataGridTemplateColumn is outside the DataGrid.Columns block.

Try moving it inside:

<DataGrid ...>
    <DataGrid.Columns>
        <DataGridTemplateColumn Width="85" Header="Kurs">
            <DataGridTemplateColumn.CellTemplate>
                <DataTemplate>
                    <RadioButton GroupName="DataGridChkBoxes" IsChecked="{Binding IsPresent2}" x:Name="rb" Content="rb" Width="50"/>
                </DataTemplate>
            </DataGridTemplateColumn.CellTemplate>
        </DataGridTemplateColumn>

        <DataGridTextColumn Binding="{Binding Nazwa}" Header="Nazwa" Width="300" IsReadOnly="True"/>
        <DataGridTextColumn Binding="{Binding KursZdarzenia}" Header="Kurs" IsReadOnly="True"/>
    </DataGrid.Columns>
</DataGrid>