ComboBox- SelectionChanged event has old value not new value

Question

C    NET 4 0  VS2010   New to WPF   I have a ComboBox on my MainWindow   I hooked the SelectionChanged event of said combo box   However  if I examine the value of the combo box in the event handler  it has the old value   This sounds more like a  SelectionChanging  event  than a SelectionChanged event     How do I get the new value of the ComboBox after the selection has actually happend   Currently   this MyComboBox SelectionChanged    new SelectionChangedEventHandler OnMyComboBoxChanged        private void OnMyComboBoxChanged object sender  SelectionChangedEventArgs e        string text   this MyComboBox Text      Note  I get the same behaviour if I use the object being passed in the event args  e g  e OriginalSource

User · Answer

The correct value to check here is the SelectedItem property     A ComboBox is a composite control with two of its parts being    The Text Part  the value in the this part corresponds to the Text property of the ComboBox  The Selector Part  i e  the  drop-down  part   The selected item in this part corresponds to the SelectedItem property      The image above was taken immediately after the ComboBox was expanded  i e  before selecting a new value    At this point both Text and SelectedItem are  Info   assuming the ComboBox items were strings  If the ComboBox items were instead all the values of an Enum called  LogLevel   SelectedItem would currently be LogLevel Info   When an item in the drop-down is clicked on  the value of SelectedItem is changed and the SelectionChanged event is raised   The Text property isn t updated yet  though  as the Text Part isn t updated until after the SelectionChanged handler is finished   This can be observed by putting a breakpoint in the handler and looking at the control     Since the Text Part hasn t been updated at this point  the Text property returns the previously selected value

User · Answer

According to MSDN  e AddedItems      Gets a list that contains the items that were selected    So you could use   private void OnMyComboBoxChanged object sender  SelectionChangedEventArgs e        string text    e AddedItems 0  as ComboBoxItem  Content as string      You could also use SelectedItem if you use string values for the Items from the sender   private void OnMyComboBoxChanged object sender  SelectionChangedEventArgs e        string text    sender as ComboBox  SelectedItem as string      or  private void OnMyComboBoxChanged object sender  SelectionChangedEventArgs e        string text     sender as ComboBox  SelectedItem as ComboBoxItem  Content as string      Since both Content and SelectedItem are objects  a safer approach would be to use  ToString   instead of as string

User · Answer

Don t complicate things for no reason  Using SelectedValue property you can easily get a selected ComboBox value like this  YourComboBoxName SelectedValue ToString     Behind the scene the SelectedValue property is defined as  SelectedValue get  set   this means you can use it to get or set the value of a ComboBox   Using SelectedItem is not an efficient way to get a ComboBox value since it requires a lot of ramifications

User · Answer

I needed to solve this in VB NET  Here s what I ve got that seems to work   Private Sub ComboBox1 SelectionChanged ByVal sender As System Object  ByVal e As System Windows Controls SelectionChangedEventArgs  Handles ComboBox AllSites SelectionChanged    Dim cr As System Windows Controls ComboBoxItem   ComboBox1 SelectedValue    Dim currentText   cr Content    MessageBox Show currentText  End Sub

User · Answer

private void OnMyComboBoxChanged object sender  SelectionChangedEventArgs e        string newItem     DataRowView  e AddedItems 0   Row ItemArray 0  ToString

User · Answer

The second option didn t work for me because the  Text element was out of scope  C  4 0 VS2008   This was my solution     string test   null  foreach  ComboBoxItem item in e AddedItems       test   item Content ToString       break

User · Answer

This worked for me   private void OnMyComboBoxChanged object sender  SelectionChangedEventArgs e        var text     sender as ComboBox  SelectedItem as ComboBoxItem  Content as string

User · Answer

You can check SelectedIndex or SelectedValue or SelectedItem property in the SelectionChanged event of the Combobox control

User · Answer

It s weird that SelectedItem holds the fresh data  whereas SelectedValue doesn t  Sounds like a bug to me  If your items in the Combobox are objects other than ComboBoxItems  you will need something like this   my ComboBox contains KeyValuePairs   var selectedItem    KeyValuePair lt string  string gt    sender as ComboBox  SelectedItem  if   selectedItem HasValue      return   string selectedValue   selectedItem Value Value      first  Value gets ref to KVPair   ComboBox SelectedItem can be null  whereas Visual Studio keeps telling me that a KeyValuePair can t be null  That s why I cast the SelectedItem to a nullable KeyValuePair lt string  string gt    Then I check if selectedItem has a value other than null  This approach should be applicable to whatever type your selected item actually is

User · Answer

Use the DropDownClosed event instead of selectionChanged if you want the current value of the combo box   private void comboBox DropDownClosed object sender  EventArgs e       MessageBox Show comboBox Text       Is really that simple

User · Answer

Following event is fired for any change of the text in the ComboBox  when the selected index is changed and when the text is changed by editing too     lt ComboBox IsEditable  True  TextBoxBase TextChanged  cbx TextChanged    gt

User · Answer

This worked for me   private void AppName SelectionChanged object sender  SelectionChangedEventArgs e       ComboBoxItem cbi    ComboBoxItem AppName SelectedItem     string selectedText   cbi Content ToString

User · Answer

I solved this by using the DropDownClosed event because this fires slightly after the value is changed

User · Answer

This should work for you      int myInt    data    object    e AddedItems   0    kid

User · Answer

private void indBoxProject SelectionChanged object sender  SelectionChangedEventArgs e        int NewProjID    e AddedItems 0  as kProject  ProjectID      this MyProject   new kProject NewProjID       LoadWorkPhase        The use of the e AddedItems 0  as kProject where kProject is a class that holds the data worked for me as it was defaulting to the RemovedItems 0  before I have made this explicit distinction   Thanks SwDevMan81 for the initial information that answered this question for me

User · Answer

From SelectionChanged event of a combobox you can get the selected item text as follow          private void myComboBox SelectionChanged  object sender  SelectionChangedEventArgs e                    ComboBoxItem comboBoxItem    ComboBoxItem  e AddedItems 0           string selectedItemText   comboBoxItem Content ToString

User · Answer

If you really need the SelectionChanged event  then the best answer is SwDevMan81 s answer  However  if you are starting with WPF  then you might want to learn how to do things the WPF way  which is different than the old Windows Forms days that used to rely on events like SelectionChanged  with WPF and Model View ViewModel pattern  you should use bindings  Here is a code example      In the Views folder   Views MyWindow xaml          lt ComboBox ItemsSource   Binding MyViewModel MyProperties  RelativeSource  RelativeSource AncestorType Window             SelectedItem   Binding MyViewModel MyProperty    RelativeSource  RelativeSource AncestorType Window      gt               In the Views folder   Views MyWindow xaml cs  public partial class MyWindow   Window       public  MyViewModelClass MyViewModel           get   return  viewModel            private set    viewModel   value              public MyWindow                 MyViewModel PropertyChanged    MyViewModel PropertyChanged              void MyViewModel PropertyChanged object sender  System ComponentModel PropertyChangedEventArgs e                if  e PropertyName     MyProperty                            Do Work                Put your logic here                     using System ComponentModel      In your ViewModel folder   ViewModels MyViewModelClass cs  public class MyViewModelClass   INotifyPropertyChanged          INotifyPropertyChanged implementation      private void NotifyPropertyChanged string propertyName         if  PropertyChanged    null    PropertyChanged this  new PropertyChangedEventArgs propertyName            public event PropertyChangedEventHandler PropertyChanged          Selected option      private string  myProperty      public  string  MyProperty           get   return  myProperty            set    myProperty   value  NotifyPropertyChanged  MyProperty                    Available options      private List lt string gt   myProperties      public  List lt string gt   MyProperties           get   return  myProperties            set    myProperties   value  NotifyPropertyChanged  MyProperties

[c#] ComboBox- SelectionChanged event has old value, not new value

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