【下载文档:  ASP.NET中获取Access新增记录Id怪现象解决方法.txt 】

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.NET中获取Access新增记录Id怪现象解决方法
复制代码 代码如下: using System; using System.Data.OleDb; namespace ConsoleApplication1 { class Program { static void Main(string[] args) { Console.WriteLine(GetUserId("dnawo")); Console.ReadKey(); } ///

/// 获取用户Id ///

/// /// static int GetUserId(string name) { using (OleDbConnection conn = new OleDbConnection(@"Provider=Microsoft.Jet.OLEDB.4.0;Data Source=F:\db1.mdb")) { conn.Open(); using (OleDbCommand cmd = new OleDbCommand()) { cmd.Connection = conn; cmd.CommandText = "select Id from UserTB where UserName='" + name + "'"; object val = cmd.ExecuteScalar(); if (val != null) return int.Parse(val.ToString()); else { cmd.CommandText = string.Format("insert into UserTB(UserName) values('{0}')", name); cmd.ExecuteNonQuery(); return GetUserId(name); } } conn.Close(); } } } } 经测试，当用户不存在时，执行上边代码后Access表中总会新增两条一样的记录：改用SQL Server数据库不会有上述问题，经多次测试又发现，若在"return GetUserId(name);"处设置断点，稍停一会也不会出现上述问题。最终代码修改如下运行正常：复制代码 代码如下: using System; using System.Data.OleDb; namespace ConsoleApplication1 { class Program { static void Main(string[] args) { Console.WriteLine(GetUserId("dnawo")); Console.ReadKey(); } ///

/// 获取用户Id ///

/// /// static int GetUserId(string name) { int id = 0; using (OleDbConnection conn = new OleDbConnection(@"Provider=Microsoft.Jet.OLEDB.4.0;Data Source=F:\db1.mdb")) { conn.Open(); using (OleDbCommand cmd = new OleDbCommand()) { cmd.Connection = conn; cmd.CommandText = "select Id from UserTB where UserName='" + name + "'"; object val = cmd.ExecuteScalar(); if (val != null) id = int.Parse(val.ToString()); else { cmd.CommandText = string.Format("insert into UserTB(UserName) values('{0}')", name); cmd.ExecuteNonQuery(); } } conn.Close(); } return id == 0 ? GetUserId(name) : id; } } }