预期组合框声明

Question

当我从 MySQL 数据库中获取组合框的值时，它似乎在第 4 行中出现预期的错误声明。有人可以帮助我吗？在这里附上我的代码

    Imports MySql.Data.MySqlClient
    Public Class Utama
     Private Sub LogoutToolStripMenuItem_Click(sender As Object, e As EventArgs) Handles LogoutToolStripMenuItem.Click
        Me.Hide()
        Dim utama As New Login
        utama.Show()
    End Sub

    Private Sub KeluarToolStripMenuItem_Click(sender As Object, e As EventArgs) Handles KeluarToolStripMenuItem.Click
        Me.Close()
    End Sub

    Private Sub SupplierToolStripMenuItem_Click(sender As Object, e As EventArgs) Handles SupplierToolStripMenuItem.Click
        Me.Hide()
        Dim supplier As New Supplier
        supplier.Show()
    End Sub

    Private Sub ProdukToolStripMenuItem_Click(sender As Object, e As EventArgs) Handles ProdukToolStripMenuItem.Click
        Me.Hide()
        Dim Produk As New Produk
        Produk.Show()
    End Sub

    Private Sub CetakToolStripMenuItem_Click(sender As Object, e As EventArgs) Handles CetakToolStripMenuItem.Click
        Me.Hide()
        Dim Cetak As New Cetak
        Cetak.Show()
    End Sub

    Dim connection As New MySqlConnection("Server=127.0.0.1;Database=pembelian;Uid=root;Pwd=;")
    Dim da As New MySqlDataAdapter("select * from supplier", connection)
    Dim dt As DataTable
    da.fill(dt)
    ComboBox1.Datasource=dt
    ComboBox1.DisplayMember = "npwp" 
    ComboBox1.ValueMember = "npwp"  
End Class

Answer 1

您需要将该代码放入一个方法中。您不能随便将任意代码放在 class 中的任何位置。唯一可以直接在 class 中的是声明。前三行是声明，所以没问题。最后四行不是。该代码应该在某处的方法内。如果您想在加载表单时执行该代码，那么它应该在 Load 事件处理程序中。这是任何初学者教程都会涵盖的非常基础的内容，因此也许您应该按照自己的方式学习这样的教程。

Answer 2

首先，创建如下所示的方法并检查异常。

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

      Try

         Dim connection As New MySqlConnection("Server=127.0.0.1;Database=pembelian;Uid=root;Pwd=;")
         Dim da As New MySqlDataAdapter("select * from supplier", connection)
         Dim dt As new DataTable
         da.fill(dt)
         ComboBox1.Datasource = dt
         ComboBox1.DisplayMember = "npwp"
         ComboBox1.ValueMember = "npwp"

      Catch ex As Exception
         MsgBox(ex.ToString)
      End Try

   End Sub

预期组合框声明

Combo Box Declaration expected

vb.net