从组合框填充文本框显示列名称

Question

我正在尝试从组合框填充文本框，但只能使用我的数据库中的列名填充它们，如下所示。

[错误示例]：

https://i.imgur.com/jyeUrKM.jpg

这是我的代码。

Private Sub Form1_Load(sender As Object, e As EventArgs) Handles MyBase.Load
    'DB PATH
    dbSource = "Data Source=(localdb)\MSSQLLocalDB;Initial Catalog=C:\USERS\MICHAEL\DOCUMENTS\GODFREYHOLMES\GHAPP2018\GHAPP2018\BIN\DEBUG\GH2018.MDF;Integrated Security=True;Connect Timeout=30;Encrypt=False;TrustServerCertificate=True;ApplicationIntent=ReadWrite;MultiSubnetFailover=False"

    'Customer ComboBox
    Try
        sql = "SELECT FirstName,LastName FROM Customer"
        cmd.CommandText = sql
        cmd.Connection = con
        con.ConnectionString = dbSource
        con.Open()
        rdr = cmd.ExecuteReader

        While rdr.Read()
            ComboCustomer.Items.Add(rdr(name:="FirstName").ToString)

        End While

    Catch ex As Exception
        MessageBox.Show("error...", "Read Error Recovery", MessageBoxButtons.OK, MessageBoxIcon.Error)


    Finally
        con.Close()
    End Try

End Sub

Private Sub ComboCustomer_SelectedIndexChanged(sender As Object, e As EventArgs) Handles ComboCustomer.SelectedIndexChanged

    If ComboCustomer.SelectedIndex <> -1 Then

        'Populate Customer Panel textboxes
        Try
            sql = "SELECT * FROM Customer WHERE FirstName = FirstName"

            'Run time parameters to avoid SQL injections

            cmd.Parameters.Add("FirstName", SqlDbType.VarChar).Value = ComboCustomer.SelectedItem.ToString
            cmd.CommandText = sql
            cmd.Connection = con
            con.ConnectionString = dbSource
            con.Open()
            rdr = cmd.ExecuteReader

            While rdr.Read

                TxtboxCustomerID.Text = ("CustomerID").ToString
                TxtBoxFirstName.Text = ("FirstName").ToString
                TxtBoxLastName.Text = ("LastName").ToString
                TxtBoxAddress.Text = ("Address").ToString
                TxtBoxZip.Text = ("Zip").ToString
                TxtBoxTele.Text = ("Telephone").ToString
                TxtBoxAccType.Text = ("AccType").ToString


            End While

        Catch ex As Exception
            MessageBox.Show("error...", "Read Error Recovery", MessageBoxButtons.OK, MessageBoxIcon.Error)

        Finally
            cmd.Parameters.Clear()
            con.Close()

        End Try

    End If