急求解决方法!!!请高手指教!

[天蝎阿辉]

Dim con As New OleDbConnection
con.ConnectionString = "Provider=Microsoft.Jet.OLEDB.4.0;Data Source=C:\db1.mdb"
con.Open()
Dim com As OleDbCommand = New OleDbCommand
com.CommandText = "SELECT Sum(金额) FROM a WHERE 日期 Between DateAdd("m",-10,getdate()) and getdate()"
TextBox1.Text = com.ExecuteScalar().ToString()
com.Dispose()
con.Close()
一开始会出现提示错误com.CommandText = "SELECT Sum(金额) FROM a WHERE 日期 Between DateAdd(""m"",-10,getdate()) and getdate()" 没有结束语句
我把这句改成com.CommandText = "SELECT Sum(金额) FROM a WHERE 日期 Between DateAdd(""m"",-10,getdate()) and getdate()"
可以运行但是点击计算按钮就会出现异常:ExecuteScalar: Connection 属性尚未初始化。

请高手指教~~

[Knight94]

to com.CommandText = "SELECT Sum(金额) FROM a WHERE 日期 Between DateAdd("m",-10,getdate()) and getdate()"

Access数据库不支持“GetDate”和“DateAdd”这两个函数，用参数来实现

例如：
com.CommandText = "SELECT Sum(金额) FROM a WHERE 日期 Between @StartDate and @EndDate"

com.Parameters.Add( "@StartDate", DateTime.Now.AddMonths( -10 ) )
com.Parameters.Add( "@StartDate", DateTime.Now )

[天蝎阿辉]

还是有同样的错误!谢谢!

[Knight94]

Sample code as follows:
'Open connection

Dim com As OleDbCommand = New OleDbCommand
com.Connection = con
com.CommandText = "SELECT Sum(金额) FROM a WHERE 日期 Between @StartDate and @EndDate"

com.Parameters.Add( "@StartDate", DateTime.Now.AddMonths( -10 ) )
com.Parameters.Add( "@StartDate", DateTime.Now )

TextBox1.Text = com.ExecuteScalar().ToString()
com.Dispose()
con.Close()

[ralpha08]

com.CommandText = "SELECT Sum(金额) FROM a WHERE 日期 Between DateAdd("m",-10,getdate()) and getdate()"
com.Connection= con
TextBox1.Text = com.ExecuteScalar().ToString()

[kandyasp]

友情帮顶

[Samen168]

com.Connection= con

[ggygd]

檢查下這句是不是有問題：
con.ConnectionString = "Provider=Microsoft.Jet.OLEDB.4.0;Data Source=C:\db1.mdb"

[天蝎阿辉]

以上方法都试过了~~还是不行~TextBox1.Text = com.ExecuteScalar().ToString()这个有异常
~未处理的“System.Data.OleDb.OleDbException”类型的异常出现在 system.data.dll 中。

[天蝎阿辉]

还是会出现同样的提示未处理的“System.Data.OleDb.OleDbException”类型的异常出现在 system.data.dll 中
TextBox1.Text = com.ExecuteScalar().ToString()