ExecuteNonQuery:连接属性尚未初始化 VB [英] ExecuteNonQuery: Connection property has not been initialized VB

问题描述

这里出现错误，不知道为什么没有打开连接.希望有人能帮助我.

Getting an error here not sure why its not opening the connection. Hoping someone can help me.

 Protected Sub Btn_Submit_Click(ByVal sender As System.Object, e As System.EventArgs) Handles Btn_Submit.Click
    Dim Sqlstr As String
    Dim con As SqlConnection
    Dim connectionString As String = "Data Source=DB\TEST;Initial Catalog=Orders;Integrated Security=True"
    Dim cmdInsert As New SqlCommand(Sqlstr, con)
    Sqlstr = "insert into customers(FirstName,LastName,Email,Phone,Address,City,State,Zip) values (@FirstName,@LastName,@Email,@Phone,@Address,@City,@State,@Zip)"
    Try
        Using connection As New SqlConnection(connectionString)
            connection.Open()
            cmdInsert.Parameters.Add("@FirstName", Data.SqlDbType.NVarChar).Value = FirstName.Text()
            cmdInsert.Parameters.Add("@LastName", Data.SqlDbType.NVarChar).Value = LastName.Text
            cmdInsert.Parameters.Add("@Email", Data.SqlDbType.NVarChar).Value = Email.Text
            cmdInsert.Parameters.Add("@Phone", Data.SqlDbType.NChar).Value = Phone.Text
            cmdInsert.Parameters.Add("@Address", Data.SqlDbType.NVarChar).Value = Address.Text
            cmdInsert.Parameters.Add("@City", Data.SqlDbType.NVarChar).Value = City.Text
            cmdInsert.Parameters.Add("@State", Data.SqlDbType.NVarChar).Value = State.Text
            cmdInsert.Parameters.Add("@Zip", Data.SqlDbType.NChar).Value = Zip.Text
            cmdInsert.ExecuteNonQuery()
            connection.Close()
        End Using
    Catch ex As Exception
        MsgBox(ex.Message)
    End Try

推荐答案

您的作用域有误 -- 在实例化并打开要尝试的实际 SQL 连接之前，您正在实例化 SqlCommand用于执行命令.

You have the wrong scope -- you're instantiating your SqlCommand before instantiating and opening the actual SQL connection you're trying to use to execute the command.

我相信这将修复您的代码(我将插入调用移至 using 范围):

I believe this is what will fix your code (I moved the insert call into the using scope):

Protected Sub Btn_Submit_Click(ByVal sender As System.Object, e As System.EventArgs) Handles Btn_Submit.Click
Dim Sqlstr As String
Dim connectionString As String = "Data Source=DB\TEST;Initial Catalog=Orders;Integrated Security=True"
Sqlstr = "insert into customers(FirstName,LastName,Email,Phone,Address,City,State,Zip) values (@FirstName,@LastName,@Email,@Phone,@Address,@City,@State,@Zip)"

Try
    Using connection As New SqlConnection(connectionString)

        connection.Open()

        Dim cmdInsert As New SqlCommand(Sqlstr, connection)  <----- **** Moved this here, changed the connection

        cmdInsert.Parameters.Add("@FirstName", Data.SqlDbType.NVarChar).Value = FirstName.Text()
        cmdInsert.Parameters.Add("@LastName", Data.SqlDbType.NVarChar).Value = LastName.Text
        cmdInsert.Parameters.Add("@Email", Data.SqlDbType.NVarChar).Value = Email.Text
        cmdInsert.Parameters.Add("@Phone", Data.SqlDbType.NChar).Value = Phone.Text
        cmdInsert.Parameters.Add("@Address", Data.SqlDbType.NVarChar).Value = Address.Text
        cmdInsert.Parameters.Add("@City", Data.SqlDbType.NVarChar).Value = City.Text
        cmdInsert.Parameters.Add("@State", Data.SqlDbType.NVarChar).Value = State.Text
        cmdInsert.Parameters.Add("@Zip", Data.SqlDbType.NChar).Value = Zip.Text
        cmdInsert.ExecuteNonQuery()

        connection.Close()
    End Using
Catch ex As Exception
    MsgBox(ex.Message)
End Try

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