C#WinForm 利用SQL临时表防止客户端重复登陆
存储过程：
set ANSI_NULLS ON
set QUOTED_IDENTIFIER ON
go
-- =============================================
-- Author:wfei
-- Create date: 2013.10.10 15:55
-- Description:
-- =============================================
ALTER PROCEDURE [dbo].[RepeatLogin]
-- Add the parameters for the stored procedure here
@username varchar(15) = null ,
@outResult int = 1 output
AS
declare @view_sql varchar(100)
--object_id函数判断操作员账号不存在（没有的登录）
if OBJECT_ID ('tempdb.dbo.##'+@username )is null
begin
--创建临时表
set @view_sql ='create table ##'+@username+'(username varchar(15))'
exec(@view_sql)
--out参数设置为0（账号没有登录）
set @outResult =0
end
--账号存在
else
--out参数为1
SqlParameter parameter1=new SqlParameter("@username",SqlDbType.VarChar,15);
SqlParameter parameter2 = new SqlParameter("@outResult", SqlDbType.Int);
string name = user.Username;
int k=multipleDB.executeProcess(name,parameter1, parameter2);
MessageBox.Show(k.ToString());
if (k==1)
{
MessageBox.Show("用户已登陆！");
}
else
{
///将登陆日志插入用户日志中
}public int executeProcess(string name,SqlParameter parameter1,SqlParameter parameter2)
{
SqlConnection?sqlcon?=?this.getcon();???//获取连接字符串????
try
{ ?????????
sqlcon.Open();???????//打开连接??????
?????? SqlCommand cmd = new SqlCommand();
cmd.Connection = sqlcon;
cmd.CommandType = CommandType.StoredProcedure;
cmd.CommandText = "RepeatLogin";
cmd.Parameters.Add(parameter1);
cmd.Parameters[0].Value = name;
cmd.Parameters.Add(parameter2).Direction=ParameterDirection.ReturnValue;
cmd.ExecuteNonQuery();
return Convert.ToInt32(cmd.Parameters[1].Value);
}
catch (SqlException e)
{
MessageBox.Show(e.ToString(),?"信息提示",?MessageBoxButtons.OK,?MessageBoxIcon.Information);
return 2;
}
finally
{
sqlcon.Close();
sqlcon.Dispose();
}
}