国产一区视频网站,久久精品国产一区二区电影,蜜桃久久精品一区二区

復制代碼代碼如下:

 
using System; 
using System.Data.OleDb; 
namespace ConsoleApplication1 
{ 
class Program 
{ 
static void Main(string[] args) 
{ 
Console.WriteLine(GetUserId("dnawo")); 
Console.ReadKey(); 
} 
/// summary> 
/// 獲取用戶Id 
/// /summary> 
/// param name="name">/param> 
/// returns>/returns> 
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(); 
} 
} 
} 
} 

經測試，當用戶不存在時，執行上邊代碼后Access表中總會新增兩條一樣的記錄：

改用SQL Server數據庫不會有上述問題，經多次測試又發現，若在"return GetUserId(name);"處設置斷點，稍停一會也不會出現上述問題。最終代碼修改如下運行正常：

復制代碼代碼如下:

 
using System; 
using System.Data.OleDb; 
namespace ConsoleApplication1 
{ 
class Program 
{ 
static void Main(string[] args) 
{ 
Console.WriteLine(GetUserId("dnawo")); 
Console.ReadKey(); 
} 
/// summary> 
/// 獲取用戶Id 
/// /summary> 
/// param name="name">/param> 
/// returns>/returns> 
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; 
} 
} 
} 

您可能感興趣的文章:

asp.net中獲取新增加記錄的ID Access版

標簽：孝感自貢萊蕪朔州西雙版納常州信陽許昌

巨人網絡通訊聲明：本文標題《.NET中獲取Access新增記錄Id怪現象解決方法》，本文關鍵詞 .NET,中,獲取,Access,新增,；如發現本文內容存在版權問題，煩請提供相關信息告之我們，我們將及時溝通與處理。本站內容系統采集于網絡，涉及言論、版權與本站無關。

婷婷综合国产,91蜜桃婷婷狠狠久久综合9色 ,九九九九九精品,国产综合av

.NET中獲取Access新增記錄Id怪現象解決方法