Question

请考虑以下代码：

 answer = today.AddDays(356)
 Dim command1 As New MySqlCommand("Insert into UserScanner (Username,Password,Address,Contact,SubStart,SubEnd,Active) VALUES('" & txtbox_username.Text.Trim & "','" & txtbox_password.Text & "','" & txtbox_add.Text & "','" & txtbox_contact.Text & "','" & today.ToString & "','" & answer.ToString & "',1)", Connection)
 command1.ExecuteNonQuery()
 MsgBox("Profile Successfuly Saved")
 Dim command2 As New MySqlCommand("Select * From userscanner WHERE Username = '" & txtbox_username.Text & "' ", Connection)
 command2.ExecuteNonQuery()
 Dim dr1 As MySqlDataReader
 dr1 = command2.ExecuteReader
 dr1.Read()
 Dim id As Integer = .Item(0)
 Dim Username As String = .Item(1)
 Dim command3 As New MySqlCommand("Insert into Trasnsaction (ID,Username,Description,Date) VALUES('" & id & "','" & Username & "','Register Account','" & today & "')", Connection)
 command3.ExecuteNonQuery()
 dr1.Close()
 Me.Close()
 frm_main.Show()

让我们关注以下几点：

 Dim command2 As New MySqlCommand("Select * From userscanner WHERE Username = '" & txtbox_username.Text & "' ", Connection)
 command2.ExecuteNonQuery()
 Dim dr1 As MySqlDataReader
 dr1 = command2.ExecuteReader

以上代码产生错误说明：

datareader中没有当前查询。

问题出在哪里？我该如何解决？

Answer 1

您可能在With行之后错过了With dr1语句，例如dr1.Read()行之后的Dim id as Integer = dr1(0) ...但我会改变它：

Dim Username As String = dr1(1)
{{1}}

如何解决＆＃34;在datareader中没有查询＆＃34;错误？

1 个答案: