我的Access数据库不会更新。在代码

Question

没有错误，我使用此代码更新数据库：

var connectionString = ConfigurationManager.ConnectionStrings["MyDatabase"].ConnectionString; 
string commandString = string.Empty; 
using (OleDbConnection con = new OleDbConnection(connectionString)) 
{ 
    con.Open(); 
    OleDbCommand command = new OleDbCommand(commandString, con); 
    commandString = "UPDATE accesscontrol SET enabled=@isEnabled WHERE proxyFor=@userNameInGrid AND currentlyLoggedOnUser=@userName"; 

    command.Parameters.AddWithValue("userName", Environment.UserName); 
    command.Parameters.AddWithValue("isEnabled", tempPerson.isBool.ToString()); 
    command.Parameters.AddWithValue("userNameInGrid", tempPerson.Name); 
    command.ExecuteNonQuery(); 
    command.Parameters.Clear(); 
} 

Answer 1

因为你使用空commandString

首先你要定义：

​​

然后你通过空commandString到OleDbCommand之后，您将值设置为变量commandString但不是OleDbCommand

OleDbCommand command = new OleDbCommand(commandString, con); 
commandString = "UPDATE accesscontrol SET enabled=@isEnabled WHERE proxyFor=@userNameInGrid AND currentlyLoggedOnUser=@userName"; 

更改您的代码：

commandString = "UPDATE accesscontrol SET enabled=@isEnabled WHERE proxyFor=@userNameInGrid AND currentlyLoggedOnUser=@userName"; 
OleDbCommand command = new OleDbCommand(commandString, con); 

UPDATE

你也应该参数名称前加上@

command.Parameters.AddWithValue("@userName", Environment.UserName); 
command.Parameters.AddWithValue("@isEnabled", tempPerson.isBool.ToString()); 
command.Parameters.AddWithValue("@userNameInGrid", tempPerson.Name);