C#中的OleDb异常“没有为一个或多个必需参数提供值."尝试从Access数据库中选择数据时 [英] OleDb Exception in c# “No value given for one or more required parameters.” while trying to Select Data from Access database

问题描述

我有以下代码:

 public DataTable opencon(PAL.property objpal)
    {
        string query = "Select UserId,Firstname,UserType from TBL_USER_LOGIN where Username=@username and Password=@password and Status=1";
        OleDbCommand objcmd = new OleDbCommand();
        objcmd.CommandText = query;
        objcmd.Connection = oldbcon;
        oldbcon.Open();
        objcmd.Parameters.Add("@username", OleDbType.VarChar).Value = objpal.username;
        objcmd.Parameters.Add("@password", OleDbType.VarChar).Value = objpal.Password;
        DataTable dt = new DataTable();
        OleDbDataAdapter adp = new OleDbDataAdapter(objcmd);
        adp.Fill(dt);
        return dt;
    }

在这里，我想根据条件从表中获取一些值， 但是当我运行此代码时，它显示以下错误:

Here I want to fetch some values from the table according to a condition, but when I run this code it shows the following error:

即使我在@username和@password中传递了正确的参数值.如何解决此错误?请帮忙.

Even though I passed the correct parameters value in @username and @password. How can I resolve this error? Please help.

推荐答案

尝试一下

string query =从[TBL_USER_LOGIN]中选择[UserId]，[Firstname]，[UserType]，其中[Username] =?和[Password] =?并且[Status] = 1]；

string query = "Select [UserId],[Firstname],[UserType] from [TBL_USER_LOGIN] where [Username]=? and [Password]=? and [Status]=1";

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