Datagrid cells align Left & Center, but not Right. Right resutls in Center alignment

Question

I have tried removing the styles, and making columns not ReadOnly, with no difference. No matter what I change, the text in the cells will only align Left or Center UNLESS the text is formatted as currency, all the fields are strings so I don't understand why that would have an effect, but it does. The amount column contains $##.## and it works, number columns, ######, should align right also but they won't.

If I add "<Setter Property="HorizontalAlignment" Value="Right"/>" to the existing CellStyle, all the columns EXCEPT the number columns align right. It is baffling.

<DataGrid x:Name="CustomerGrid" Grid.Row="2" Grid.ColumnSpan="3" Margin="5,10,5,5" 
                        ItemsSource="{Binding Customers}" SelectedItem="{Binding SelectedCustomer}"
                        Height="Auto" Width="Auto" SelectionMode="Single"  AutoGenerateColumns="False" CanUserAddRows="False" CanUserResizeColumns="True"
                        SelectionUnit="FullRow"  Background="Transparent" CanUserResizeRows="False" CanUserReorderColumns="False" CanUserSortColumns="True"
                        ScrollViewer.HorizontalScrollBarVisibility="Auto" ScrollViewer.VerticalScrollBarVisibility="Auto" GridLinesVisibility="All"
                        VerticalAlignment="Stretch" AlternationCount="2">

            <DataGrid.ColumnHeaderStyle>
                <Style TargetType="{x:Type DataGridColumnHeader}">
                    <Setter Property="FontWeight" Value="SemiBold"/>
                    <Setter Property="HorizontalContentAlignment" Value="Center"/>
                </Style>
            </DataGrid.ColumnHeaderStyle>

            <DataGrid.CellStyle>
                <Style TargetType="DataGridCell" >
                    <Style.Triggers>
                        <Trigger Property="IsSelected" Value="True">
                            <Setter Property="Foreground" Value="{DynamicResource {x:Static SystemColors.ControlTextBrushKey}}"/>
                            <Setter Property="Background" Value="Yellow"/>
                            <Setter Property="BorderBrush" Value="Transparent"/>
                            <Setter Property="BorderThickness" Value="0"/>
                        </Trigger>
                    </Style.Triggers>
                </Style>
            </DataGrid.CellStyle>

            <DataGrid.RowStyle>
                <Style TargetType="DataGridRow">
                    <Setter Property="ContextMenu" Value="{StaticResource RowMenu}"/>
                    <Setter Property="Height" Value="25"/>
                    <Setter Property="FontSize" Value="12"/>
                    <Style.Triggers>
                        <Trigger Property="AlternationIndex" Value="1">
                            <Setter Property="Background" Value="WhiteSmoke"/>
                            <Setter Property="FontWeight" Value="Normal"/>
                        </Trigger>
                        <Trigger Property="IsMouseOver" Value="True">
                            <Setter Property="Background" Value="LightCyan"/>
                        </Trigger>
                    </Style.Triggers>
                </Style>
            </DataGrid.RowStyle>

            <!--hide the default button at the beginning of each row-->
            <DataGrid.RowHeaderStyle>
                <Style TargetType="{x:Type DataGridRowHeader}">
                    <Setter Property="Width" Value="0"/>
                </Style>
            </DataGrid.RowHeaderStyle>

            <DataGrid.Columns>
                <DataGridTemplateColumn Header="Customer Name" MinWidth="200" IsReadOnly="True">
                    <DataGridTemplateColumn.CellTemplate>
                        <DataTemplate>
                            <TextBlock Text="{Binding FullName}" TextAlignment="Left" Margin="5,0,0,0" VerticalAlignment="Center" ToolTip="{Binding FullName}"/>
                        </DataTemplate>
                    </DataGridTemplateColumn.CellTemplate>
                </DataGridTemplateColumn>

                <DataGridTemplateColumn Header="Customer Number" MinWidth="120" IsReadOnly="True" >
                    <DataGridTemplateColumn.CellTemplate>
                        <DataTemplate>
                            <TextBlock Text="{Binding CustomerNumber}" Margin="0,0,5,0" TextAlignment="Right" VerticalAlignment="Center"/>
                        </DataTemplate>
                    </DataGridTemplateColumn.CellTemplate>
                </DataGridTemplateColumn>

                <DataGridTemplateColumn Header="Bill To Cust Number" MinWidth="120" IsReadOnly="True">
                    <DataGridTemplateColumn.CellTemplate>
                        <DataTemplate>
                            <TextBlock Text="{Binding BillToCustNumber}" Margin="0,0,5,0" TextAlignment="Right" VerticalAlignment="Center"/>
                        </DataTemplate>
                    </DataGridTemplateColumn.CellTemplate>
                </DataGridTemplateColumn>

<DataGridTemplateColumn Header="Payment Amount" MinWidth="150" IsReadOnly="True">
                    <DataGridTemplateColumn.CellTemplate>
                        <DataTemplate>
                            <TextBlock Text="{Binding Amount}" HorizontalAlignment="Right" Margin="0,0,5,0" VerticalAlignment="Center"/>
                        </DataTemplate>
                    </DataGridTemplateColumn.CellTemplate>
                </DataGridTemplateColumn>

            </DataGrid.Columns>
        </DataGrid>

Answer 1

I tried using TextAlignment="Right" for cells and it set them to the right side. When I tried your code with minor tweaking, it worked like this: Datagrid cells align Left & Center, but not Right.

Here is the change:

<DataGridTemplateColumn Header="Payment Amount" MinWidth="150" IsReadOnly="True">
            <DataGridTemplateColumn.HeaderStyle>
                <Style TargetType="{x:Type DataGridColumnHeader}">
                    <Setter Property="HorizontalContentAlignment" Value="Right" />
                </Style>
            </DataGridTemplateColumn.HeaderStyle>
            <DataGridTemplateColumn.CellTemplate>
                <DataTemplate>
                    <TextBlock Text="{Binding Amount}" TextAlignment="Right" Margin="0,0,5,0" VerticalAlignment="Center"/>
                </DataTemplate>
            </DataGridTemplateColumn.CellTemplate>
        </DataGridTemplateColumn>

And here is my class Customer

public class Customer
{
public string? FullName { get; set; }
public string? CustomerNumber { get; set; }
public string? BillToCustNumber { get; set; }

private decimal _amount { get; set; }
public string? Amount
{
    get => _amount.ToString("$0.00");
    set
    {
        if (decimal.TryParse(value, out decimal number))
            _amount = number;
    }
}
}

So, could you provide little bit more information (code with sample data) to test it? Or even show image/link to how you want it? Sorry if I misunderstood the question.