VB.NET: how to prevent user input in a ComboBox

Question

How do you prevent user input in a ComboBox so that only one of the items in the defined list can be selected by the user?

Answer 1

this is the most simple way but it works for me with a ComboBox1 name

SOLUTION on 3 Basic STEPS:

step 1.

Declare a variable at the beginning of your form which will hold the original text value of the ComboBox. Example:

     Dim xCurrentTextValue as string

step 2.

Create the event combobox1 key down and Assign to xCurrentTextValue variable the current text of the combobox if any key diferrent than "ENTER" is pressed the combobox text value keeps the original text value

Example:

Private Sub ComboBox1_KeyDown(sender As Object, e As KeyEventArgs) Handles ComboBox1.KeyDown

    xCurrentTextValue = ComboBox1.Text

    If e.KeyCode <> Keys.Enter Then
        Me.ComboBox1.Text = xCmbItem
    End If

End Sub

step 3.

Validate the when the combo text is changed if len(xcurrenttextvalue)> 0 or is different than nothing then the combobox1 takes the xcurrenttextvalue variable value

Private Sub ComboBox1_TextChanged(sender As Object, e As EventArgs) Handles ComboBox1.TextChanged
    If Len(xCurrentTextValue) > 0 Then
        Me.ComboBox1.Text = xCurrentTextValue

    End If
End Sub

========================================================== that's it,

Originally I only tried the step number 2, but I have problems when you press the DEL key and DOWN arrow key, also for some reason it didn't validate the keydown event unless I display any message box

---

!Sorry, this is a correction on step number 2, I forgot to change the variable xCmbItem to xCurrentTextValue, xCmbItem it was used for my personal use

THIS IS THE CORRECT CODE

xCurrentTextValue = ComboBox1.Text

If e.KeyCode <> Keys.Enter Then
    Me.ComboBox1.Text = xCurrentTextValue
End If

Answer 2

Set the ReadOnly attribute to true.

Or if you want the combobox to appear and display the list of "available" values, you could handle the ValueChanged event and force it back to your immutable value.

Answer 3

Set the DropDownStyle property of the combobox to DropDownList. This will allow only items in the list to be selected and will not allow any free-form user input.