语法的问题

[zhaozipeng]

这个语句
Imports System.Data.OleDb
Module Module1
Public source = "Provider=Microsoft.Jet.OLEDB.4.0;Data Source="
source = source + "D:\js.mdb"
Public conn As New OleDbConnection(source)
conn.Open()
End Module
提示第二行SOURCE没声明
第四行CONN没声明
怎么改啊

[水如烟]

Public conn As OleDbConnection=New OleDbConnection(source)

[水如烟]

Public source = "Provider=Microsoft.Jet.OLEDB.4.0;Data Source=D:\js.mdb"

[水如烟]

Module Module1
'这时设变量
Public source = "Provider=Microsoft.Jet.OLEDB.4.0;Data Source="
Public conn As OleDbConnection=New OleDbConnection(source)
’这里操作代码
Public Sub a()
source = source + "D:\js.mdb"
conn.Open()
End Sub
End Module

[AntingZ]

source = source + "D:\js.mdb"
conn.Open()
这种语句只能写在函数，方法里面

外面只能定义变量（可以在定义的时候赋初始值，比如您的模块内的第一，三行）

[zhaozipeng]

还是报同样的错误啊

[水如烟]

Module Module1
'这时设变量
Public source = "Provider=Microsoft.Jet.OLEDB.4.0;Data Source=D:\js.mdb"
Public conn As OleDbConnection=New OleDbConnection(source)
’这里操作代码
Public Sub a()
conn.Open()
End Sub
End Module

[zhaozipeng]

好的，谢谢

[AntingZ]

Imports System.Data.OleDb
Module Module4
'这时设变量
Public source As String = "Provider=Microsoft.Jet.OLEDB.4.0;Data Source="
Public conn As OleDbConnection
'这里操作代码
Public Sub a()
source = source + "D:\js.mdb"
conn = New OleDbConnection(source)
conn.Open()
End Sub
End Module

[zhaozipeng]

现在一到调用数据库的语句就提示如下错误：
未处理的“System.InvalidOperationException”类型的异常出现在 system.windows.forms.dll 中。

其他信息: ExecuteReader: Connection 属性尚未初始化。
调用数据库的语句如下
Dim InsertCmd As String = "select * from admin where username='" + username.Text + "'"
Dim cmd As New OleDbCommand(InsertCmd, conn)
Dim dr As OleDbDataReader = cmd.ExecuteReader
If dr.Read() Then
If dr.GetString(2) = userpass.Text Then
Hide()
user = username.Text
Dim mainform As New mainForm
mainform.Show()
Else
msg.Text = "密码错误"
End If
Else
msg.Text = "帐号错误"
End If

[水如烟]

喂，楼上，怎么今天这么有闲？

[水如烟]

Module Module1
Public source = "Provider=Microsoft.Jet.OLEDB.4.0;Data Source=D:\js.mdb"
Public conn As OleDbConnection=New OleDbConnection(source)
End Module

‘’
Dim InsertCmd As String = "select * from admin where username='" + username.Text + "'"
Dim cmd As New OleDbCommand(InsertCmd, conn)
‘’‘’
conn.Open
Dim dr As OleDbDataReader = cmd.ExecuteReader
If dr.Read() Then
If dr.GetString(2) = userpass.Text Then
Hide()
user = username.Text
Dim mainform As New mainForm
mainform.Show()
Else
msg.Text = "密码错误"
End If
Else
msg.Text = "帐号错误"
End If
'''''
Conn.Close

[zhaozipeng]

好了，谢谢各位