Question

这是一个鳕鱼，当它为组合框它做了它来了我的一个消息我不喜欢“canot绑定新值member.parameter name：value”

        Dim sql3 As String
           Dim dt4 As New DataTable

            sql3 = "SELECT     class.class_name, teacher.first_name, course.cours_name, class.class_char" _
    & " FROM         class INNER JOIN" _
    & "                      lecture ON class.class_num = lecture.class_num INNER JOIN" _
    & "                      course ON lecture.cours_num = course.cours_num INNER JOIN" _
    & "                      teacher ON lecture.teacher_id = teacher.teacher_id" _
    & " WHERE     (class.class_name = '" & cbox_class.Text & "') AND(teacher.first_name = '" & cbox_teacher_name.Text & "')"
            Dim da5 As New SqlDataAdapter()
            da5 = New SqlDataAdapter(sql3, conn)
            da5.Fill(dt4)
            cbox_cours.DropDownStyle = ComboBoxStyle.DropDownList
        cbox_cours.DataSource = dt4
            cbox_cours.DisplayMember = "cours_name"
            cbox_cours.ValueMember = "cours_num"

Answer 1

您的查询未返回cours_num

更改

"SELECT     class.class_name, teacher.first_name, course.cours_name, class.class_char" _

到

"SELECT     class.class_name, teacher.first_name, course.cours_name, course.cours_num, class.class_char" _

Answer 2

您的查询似乎没有返回cours_num字段。您必须在查询中包含缺少的字段，或更正ValueMember值，以便使用正确的字段。

作为旁注，您应该知道您当前的代码是Sql injection attacks的广泛开放。您应该使用参数化查询，而不是连接UI控件中的值。

Winforms combobox canot绑定新值member.parameter name：value

2 个答案: