How to get rid of annoying HorizontalContentAlignment binding warning?

This worked for me. Put this in your Application.xaml file.

<Application.Resources>    <Style TargetType="ComboBoxItem">        <Setter Property="HorizontalContentAlignment" Value="Left" />        <Setter Property="VerticalContentAlignment" Value="Center" />    </Style></Application.Resources>

from...

http://social.msdn.microsoft.com/Forums/en-US/wpf/thread/42cd1554-de7a-473b-b977-ddbd6298b3d0

I don't know if after more than a year your are still interested in this problem but my solution was to explicitly write in the style the value for this. For example:

<Style x:Key="{x:Type ComboBoxItem}" TargetType="{x:Type ComboBoxItem}">    <Setter Property="HorizontalContentAlignment" Value="Stretch"/>

And that simply solved that problem.

I just want to mention I struggled with a similar problem for two days (mine was a "Windows Data Error 4" error, complaining about HorizontalContentAlignment and VerticalContentAlignment).

The most common suggested solution (adding the Horizontal/VerticalContentAlignment Style to your element, or even to the App.xaml) does NOT always solve the problem.

Eventually, I discovered something unique to my own situation - I hope it can be of help to someone: If you are using the FilterEventHandler, don't unsubscribe it before resubscribing!

My old code kept on generating that "Data Error 4" message whenever I changed the Channel Filter (which calls UpdateCorporatesList):

// This code generates errorsprivate void UpdateCorporatesList(){    this.CorporatesViewSource.Filter -= new FilterEventHandler(ApplyCorporateFilter);    if (this.ChannelFilter != null)    {        this.CorporatesViewSource.Filter += new FilterEventHandler(ApplyCorporateFilter);    }    else    {        this.CorporateFilter = null;    }}private void ApplyCorporateFilter(object sender, FilterEventArgs e){    SalesCorporate customer = e.Item as SalesCorporate;    var currentChannel = this.Channels.FirstOrDefault(x => x.ID == this.ChannelFilter).Description;    if ((customer.ID != null) && (customer.Channel != currentChannel))    {        e.Accepted = false;    }}

...so I changed it to re-subscribe to the FilterEventHandler every time, and rather put the check for a null on Channel Filter in the event-handling method.

// This code works as intendedprivate void UpdateCorporatesList(){    this.CorporatesViewSource.Filter += new FilterEventHandler(ApplyCorporateFilter);    if (this.ChannelFilter == null)    {        this.CorporateFilter = null;    }}private void ApplyCorporateFilter(object sender, FilterEventArgs e){    var currentChannel = this.Channels.FirstOrDefault(x => x.ID == this.ChannelFilter);    if (currentChannel.ID == null)    {        return;    }    SalesCorporate customer = e.Item as SalesCorporate;    if ((customer.ID != null) && (customer.Channel != currentChannel.Description))    {        e.Accepted = false;    }}

Et Voila! No more errors :-)