Changing the selected value of a drop down based on the selected value of another drop down in VB.Net

I have a dropdown box which is used to select a user from a database. I am then populating a number of textboxes with the user information from the database. I want to populate a dropdown box, which holds the user's role, dependent on which user is selected from the first drop down box.

Here is my code:

    Dim currentUser As String = editUserDropDown.SelectedValue
    Dim getUserDetails = "Select aspnet_Users.UserName, aspnet_Roles.RoleName, [User Details].EmployeeName, [User Details].EmployeeAddress, [User Details].PersonalEmailAddress FROM aspnet_Users INNER JOIN [User Details] ON aspnet_Users.UserId = [User Details].UserId CROSS JOIN aspnet_Roles WHERE (aspnet_Users.UserName = '" & currentUser & "')"
    Dim getUserDetailsCmd As New SqlClient.SqlDataAdapter(getUserDetails, DBConn)
    Dim getUserDetailsDS As New DataSet
    getUserDetailsCmd.Fill(getUserDetailsDS)

    Dim username = getUserDetailsDS.Tables(0).Rows(0).Item(0)
    Dim 开发者_运维百科roleName = getUserDetailsDS.Tables(0).Rows(0).Item(1)
    Dim name = getUserDetailsDS.Tables(0).Rows(0).Item(2)
    Dim address = getUserDetailsDS.Tables(0).Rows(0).Item(3)
    Dim email = getUserDetailsDS.Tables(0).Rows(0).Item(4)


    userNameTxt.Text = username

    roleSelect.SelectedValue = roleName

    nameTxt.Text = name
    addressTxt.Text = address.Trim()
    emailTxt.Text = email

any help is greatly appreciated

You have to do this by doing a Post-back on the fist select drop down and then getting the content for the second one depending of the selection made on the first...

Hoped that helped!