Unfortunately, TextSearch.Text doesn't work in a DataTemplate. Otherwise you could have done something like this
<ComboBox ...>
<ComboBox.ItemContainerStyle>
<Style TargetType="{x:Type ComboBoxItem}">
<Setter Property="TextSearch.Text">
<Setter.Value>
<MultiBinding StringFormat="{}{0}: {1}">
<Binding Path="BidServiceCategoryId"/>
<Binding Path="BidServiceCategoryName"/>
</MultiBinding>
</Setter.Value>
</Setter>
</Style>
</ComboBox.ItemContainerStyle>
</ComboBox>
However this won't work, so I see two solutions to your problem.
First way
You set IsTextSearchEnabled to True for the ComboBox, override ToString in your source class and change the MultiBinding in the TextBlock to a Binding
Xaml
<ComboBox ...
IsTextSearchEnabled="True">
<ComboBox.ItemTemplate>
<DataTemplate>
<TextBlock Text="{Binding}"/>
</DataTemplate>
</ComboBox.ItemTemplate>
Source class
public class TheNameOfYourSourceClass
{
public override string ToString()
{
return String.Format("{0}: {1}", BidServiceCategoryId, BidServiceCategoryName);
}
//...
}
Second Way
If you don't want to override ToString I think you'll have to introduce a new Property in your source class where you combine BidServiceCategoryId and BidServiceCategoryName for the TextSearch.TextPath. In this example I call it BidServiceCategory. For this to work, you'll have to call OnPropertyChanged("BidServiceCategory"); when BidServiceCategoryId or BidServiceCategoryName changes as well. If they are normal CLR properties, you can do this in set, and if they are dependency properties you'll have to use the property changed callback
Xaml
<ComboBox ...
TextSearch.TextPath="BidServiceCategory"
IsTextSearchEnabled="True">
<ComboBox.ItemTemplate>
<DataTemplate>
<TextBlock DataContext="{Binding}">
<TextBlock.Text>
<MultiBinding StringFormat="{}{0}: {1}">
<Binding Path="BidServiceCategoryId" />
<Binding Path="BidServiceCategoryName" />
</MultiBinding>
</TextBlock.Text>
</TextBlock>
</DataTemplate>
</ComboBox.ItemTemplate>
Source class
public class TheNameOfYourSourceClass
{
public string BidServiceCategory
{
get
{
return String.Format("{0}: {1}", BidServiceCategoryId, BidServiceCategoryName);
}
}
private string m_bidServiceCategoryId;
public string BidServiceCategoryId
{
get
{
return m_bidServiceCategoryId;
}
set
{
m_bidServiceCategoryId = value;
OnPropertyChanged("BidServiceCategoryId");
OnPropertyChanged("BidServiceCategory");
}
}
private string m_bidServiceCategoryName;
public string BidServiceCategoryName
{
get
{
return m_bidServiceCategoryName;
}
set
{
m_bidServiceCategoryName = value;
OnPropertyChanged("BidServiceCategoryName");
OnPropertyChanged("BidServiceCategory");
}
}
}
