Programmatically replace GridView cell contents on load

Question

I am working on a program in WPF for the first time. I have a ListView in GridView mode displaying data from a bound dataset (which is grabbed from a database).

In my database, "date of birth" is not a required field. As such, any record without a dob had the value set to DateTime.MinValue. On each of these minimum value dates, the date shows in the cell as 01/01/0001. I am trying to find a way to either format the cell so that DateTime.MinValue doesn't show, or replace each MinValue with "".

My thought was to either use the "Loaded" event of the textblock the date is in and replace each instance of "01/01/0001", or loop through the dataset before sending it to the GridView and remove/replace them there. I've not had any luck figuring out how to do either.

My xaml code for the GridView is:

<Grid>
    <ListView x:Name="resultsListView" GridViewColumnHeader.Click="GridViewColumnHeaderClickedHandler" Margin="0,54,0,28" ItemsSource="{Binding Path=Table}">
    <ListView.View>
    <GridView>
        <GridViewColumn DisplayMemberBinding="{Binding Path=LastName}"
            Header="Last Name" 
            Width="150"/>
        <GridViewColumn DisplayMemberBinding="{Binding Path=FirstName}" 
            Header="First Name"
            Width="100"/>
        <GridViewColumn DisplayMemberBinding="{Binding Path=MiddleName}" 
            Header="Middle Name"
            Width="100"/>
        <GridViewColumn Header="Date of Birth" Width="100">
            <GridViewColumn.CellTemplate>
                <DataTemplate>
                    <TextBlock TextAlignment="Justify" Text="{Binding Path=DateOfBirth, StringFormat='{}{0:MM/dd/yyyy}'}" Loaded="TextBlock_Loaded" />
                </DataTemplate>
            </GridViewColumn.CellTemplate>
        </GridViewColumn>
    </GridView>
    </ListView.View>
    </ListView>
</Grid>

Code for the DataSet:

private void FillListView(DataSet ds)
{
    if (resultsListView.Items.Count != 0)
    {
        resultsListView.Items.Clear();
    }
    resultsListView.DataContext = ds.Tables[0].DefaultView;
}

Any advice on how to show blanks for DateTime.MinValue in my GridView would be much appreciated!

Answer 1

I would make an IValueConverter that deals with this, and include it in your binding expression.

In your resources:

<local:DateTimeConverter x:Key="DateTimeConverter" />

Then update your binding:

<TextBlock Text="{Binding Path=DateOfBirth, 
                          Converter={StaticResource DateTimeConverter},
                          ConverterParameter='MM/dd/yyyy'}" />

Then define the class:

public class DateTimeConverter : IValueConverter

This has two methods. You need only to implement Convert (unless you're planning on using two-way binding). In this method, you can take the format string via a paramater (as I've passed in the binding expression above) and also check for DateTime.MinValue and return a blank string.