C# Update Combobox text after SelectedItemChange

Question

I have a combobox that i would like the physically displayed text to always remain the same.

I want the user to select an item which would then get passed in but then for the actual text on the combobox to remain the same.

on the

FileBox_SelectionChanged(object sender, SelectionChangedEventArgs e)

event i find out which item has been selected with

 if (((ComboBox)sender).SelectedItem != null)
        {
            if (((ComboBox)sender).SelectedItem.ToString() == "New File")
            {

            }
        }

(i will process this more later)

I then try and update the text back to being 'File'.

I have tried numerous approaches which dont seem to work.

I've tried simply doing

FileBox.text = "File";

this.Dispatcher.Invoke(() =>
        {
            FileBox.Text = "File";
        });

FileBox.SelectedItem = "File";

When debugging it does actually seem like the .Text property gets updated, but it then seems to get overridden when the event finishes. For testing i have a button that does:

var text = FileBox.Text;
FileBox.Text = "File";

When i have selected "New File" the var text == New File

And the FileBox.Text code here works and updates it back to File

Do i need to set the text again outside of the SelectionChanged event, and if so how would i go about doing this?

Thanks

EDIT

I do not think this is a duplicate of the one posted as he wants his default to dissapear when something is selected, i want it to reappear

So basically, you want your combobox to have it's default selected item "Files" to be selected again once your code gets the item selected by the user? — Mac, Sep 07 '18 at 10:06
Possible duplicate of [Watermark Behavior for ComboBox](https://stackoverflow.com/questions/37211869/watermark-behavior-for-combobox) — dhilmathy, Sep 07 '18 at 10:15
Can you post your xaml for combobox? How do you populate the data? — Mac, Sep 07 '18 at 10:16

score 1 · Accepted Answer · answered Sep 07 '18 at 11:10

The approach is actually not ideal, you should use MVVM pattern, but this is my answer to your question, hope it helps.

<ComboBox x:Name="FileBox"
                  SelectedIndex="0"
                  SelectionChanged="FileBox_OnSelectionChanged"
                  Width="180" Height="50" >

Code-behind

private void FileBox_OnSelectionChanged(object sender, SelectionChangedEventArgs e)
        {
            var fileBox = sender as ComboBox;

            if (fileBox != null)
            {
                var selectedItem = fileBox.SelectedItem;

                // get the selected item.
                Debug.WriteLine(selectedItem);

                fileBox.SelectionChanged -= FileBox_OnSelectionChanged;
                fileBox.SelectedIndex = 0;
                fileBox.SelectionChanged += FileBox_OnSelectionChanged;
            }
        }

Assuming that this is how you populate your control:

private void PopulateFileData()
        {
            FileDataList = new List<FileData>
            {
                new FileData{ FileName = "Files", Path = "" },
                new FileData{ FileName = "File 123", Path = @"c:\file1.txt" },
                new FileData{ FileName = "File 456", Path = @"c:\file2.txt" }
            };
        }

        private void FillComboBox()
        {
            foreach (FileData file in FileDataList)
            {
                FileBox.Items.Add(file.FileName);
            }
        }

Check your output window.

C# Update Combobox text after SelectedItemChange

1 Answers1