ComboBox DataSource Binding in Visual Basic

ComboBox comes in handy for connecting to a database using ComboBox DataSource binding. In this way, we can use data sources for getting selection input from user. Before we start the exercise, understand the following terms for ComboBox binding:

• Data Source: This is used to fill the Items Collection of ComboBox with the data source. If we have a database as a data source, then we may use Table binding source as the data source for ComboBox.
• Display Member: This property from the data source is shown in the list as Items Collection of ComboBox.
• Value Member: This value is returned from the data source when Selected Value property of ComboBox is accessed.
• Selected Value: Use this if you want to bind the selected value to a property in data source.

Now, follow the steps below:

1. Add our Access Test_Database from the previous post to the project. In case you haven’t read the post, get the information here.
2. Place a new ComboBox1 and Label1 to the project Form Design.

   

3. Select the option Use Data Bound Items from the ComboBox Tasks:

   

4. Select Table1 for the Data Source property. A new binding source Table1BindingSource will be created and selected itself.

   

5. Select FirstName as the Display Member and Value Member. Leave SelectedValue to (none).

   

6. Run the application. You can see that ComboBox is showing the list of First Names from the data source:

Get Value of Selected Item from ComboBox DataSource

To get the value of selected item from ComboBox, paste the following code inside ComboBox1_SelectedIndexChanged sub:

If Not ComboBox1.SelectedValue = Nothing Then
            Label1.Text = ComboBox1.SelectedValue.ToString
        End If

The complete code looks like this:

Public Class Form1

    Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
        'TODO: This line of code loads data into the 'Test_DatabaseDataSet.Table1' table. 
        'You can move, or remove it, as needed.
        Me.Table1TableAdapter.Fill(Me.Test_DatabaseDataSet.Table1)
    End Sub

    Private Sub ComboBox1_SelectedIndexChanged(ByVal sender As System.Object, _
        ByVal e As System.EventArgs) Handles ComboBox1.SelectedIndexChanged
        If Not ComboBox1.SelectedValue = Nothing Then
            Label1.Text = ComboBox1.SelectedValue.ToString
        End If
    End Sub
End Class

Now the Label1 text is updated whenever user changes the selection:

You may want to retrieve the value of Age instead of first name for the selected item. To do this, we need to modify the Value Member property. Go to ComboBox Tasks and select Age for Value Member.

Run the application. Label1 is updated with the Age of the selected Name:

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