“对象引用未设置为对象的实例”错误

本文介绍了“对象引用未设置为对象的实例”错误的处理方法，对大家解决问题具有一定的参考价值，需要的朋友们下面随着小编来一起学习吧！ 问题描述

我想创建连接字符串并将其用于我的应用程序中的所有表单但显示错误。 下面是我的代码，但显示错误对象引用没有设置为对象的实例 请帮忙!!!!!!! 我尝试过：

I want to create connection string and use it to all forms in my application but is showing error. Below is my code but its showing error "Object reference not set to an instance of an object" Please Help!!!!!!! What I have tried:

mports System.Data.SqlClient Imports System.Data.OleDb Module sqlserverconnectionstring Public connsql As SqlConnection Dim connstr As String Public Sub sqlserverconnection() Try connstr = "Provider=SQLOLEDB.1; Data Source=" & My.Settings.sqlservername & ";Initial Catalog=" & My.Settings.sqlDBname & ";Password=" & My.Settings.sqlPswd & ";User ID=" & My.Settings.sqlUserName connsql.Open() Catch ex As Exception MsgBox(ex.Message.ToString) End Try End Sub Public Sub sqlserverdisconnectdatabase() Try connsql.Close() Catch myerror As SqlClient.SqlException End Try End Sub End Module

推荐答案

您尚未实例化 connsql 。请参阅粗体代码： You haven't instantiated connsql. See bolded code: connstr = "Provider=SQLOLEDB.1; Data Source=" & My.Settings.sqlservername & ";Initial Catalog=" & My.Settings.sqlDBname & ";Password=" & My.Settings.sqlPswd & ";User ID=" & My.Settings.sqlUserName connsql = New SqlConnection(connstr) connsql.Open()

connstr =Data Source =& My.Settings.sqlservername& ;初始目录=& My.Settings.sqlDBname& ;密码=& My.Settings.sqlPswd& ;用户ID =& My.Settings.sqlUserName connsql =新的SqlConnection（connstr） connsql.Open（） connstr = "Data Source=" & My.Settings.sqlservername & ";Initial Catalog=" & My.Settings.sqlDBname & ";Password=" & My.Settings.sqlPswd & ";User ID=" & My.Settings.sqlUserName connsql = New SqlConnection(connstr) connsql.Open()