如果选择 Combobox vb.net mysql，则文本框中的数据库值

我无法弄清楚我的问题没有错误但是组合框中的值没有从 mysqldatabase 显示这里是我的代码

    Private Sub Form2_Load(sender As Object, e As EventArgs) Handles MyBase.Load

    Dim conn As New MySqlConnection

    conn.ConnectionString = "server=localhost;user vbid=root;password=admin;database=dnidb"

    Dim reader As MySqlDataReader

    Try
        conn.Open()
        Dim query As String
        query = "select * from dnidb.hargapro where NamaP = '" & ComboBox1.Text & "'"
        command = New MySqlCommand(query, conn)
        reader = command.ExecuteReader
        While reader.Read
            TextBox8.Text = reader.GetInt32("HargaP")
          End While
        conn.Close()
    Catch ex As Exception
        MessageBox.Show(ex.Message)
    Finally
        conn.Dispose()
    End Try


End Sub

这段代码没有错误，但没有在组合框中显示任何内容，我尝试在组合框_selectedindexchanges上制作这个圆锥体，而组合框中没有显示同样的内容

我只是按照这里的代码https://www.youtube.com/watch?v=HfnoGEmRGvc