CODEWITHSUNDEEP
wpfcombobox
parfum
parfum

Reputation: 347

wpf comboBox selectedIndex=0 is not working

.xaml

<ComboBox Grid.Row="0" Grid.Column="1" x:Name="cbx_srchResOrg" HorizontalAlignment="Stretch" Style="{DynamicResource ComboBoxStyle}"
                      ItemsSource="{Binding InfoCombo}" SelectedIndex="0" DisplayMemberPath="Dis_name" SelectedValuePath="Hide_id" SelectedItem="{Binding SelectInfo}"/>

Here is a part of my source code. Why 'SelectedIndex=0' is not working? I want to select [0] value to default at first time, but it just empty box at run time. There are no errors except it. How can I fix it?

Upvotes: 5

Views: 9246

Answers (4)

Wingjam
Wingjam

Reputation: 802

You can also use Mode=OneWayToSource in the SelectedItem binding with SelectedIndex="0".

In your case:

<ComboBox Grid.Row="0" 
          Grid.Column="1" 
          x:Name="cbx_srchResOrg" 
          HorizontalAlignment="Stretch" 
          Style="{DynamicResource ComboBoxStyle}"
          ItemsSource="{Binding InfoCombo}" 
          SelectedIndex="0" 
          DisplayMemberPath="Dis_name" 
          SelectedValuePath="Hide_id" 
          SelectedItem="{Binding SelectInfo, Mode=OneWayToSource}"/>

Like others said, it binds two way by default, so if the property binded to it (SelectInfo) is null, it will also be set to null.

Upvotes: 3

Vecchiasignora
Vecchiasignora

Reputation: 1315

you have bind SelectedItem to SelectInfo, you should set value(in your viewmodel) to SelectInfo as default, for example

SelectInfo = InfoCombo[0] or something other whatevere you want to set as default value

Upvotes: 1

Gopichandar
Gopichandar

Reputation: 2842

As Hej said, you have binded the SelectedItem with a property in your view model which was null.

You can fix this by assigning the SelectedItem in your Viewmodel constructor

Public MyViewModel()
{
    SelectInfo = InfoCombo[0];
}

Upvotes: 4

Hej
Hej

Reputation: 91

Because you are already binding to SelectedItem. It binds two way by default, so if the property binded to it(SelectInfo) is null, it will also be set to null.

Upvotes: 3

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