getvalue(2)获得空 [英] getvalue(2) get null

问题描述

大家好

我有这种语法

hi all

i have this syntax

lcuser = this.txtUserName.Value;
       lcpassword = this.txtPassword.Value;
       SqlConnection con = new SqlConnection("Data source = UIS-PC\\SQLEXPRESS; Initial Catalog=Database1; integrated security = SSPI;");
       SqlCommand selectid = new SqlCommand("SELECT cuser, cpassword, cbranch, caddress FROM branch", con);
       con.Open();
       SqlDataReader BranchReader = selectid.ExecuteReader();
       int branch = BranchReader.GetOrdinal("caddress");
       while (BranchReader.Read())
       {

           gcbranch = BranchReader.GetName(2).ToString();
           gcaddress = BranchReader[2].ToString();
           gcuser = BranchReader.GetValue(3).ToString();
           gcpassword = BranchReader.GetValue(2).ToString();

尽管我已将其填入表数据库中，但GetValue(2)显示为空
GetValue(2)有时显示为空，尽管它们具有数据

在此先感谢

GetValue(2) shows null although i have it filled in the table database
GetValue(2) some times shows empty although they have data

thanks in advance

推荐答案

try

try

gcbranch = BranchReader[2].ToString();
gcaddress = BranchReader[3].ToString();
gcuser = BranchReader[0].ToString();
gcpassword = BranchReader[1].ToString();

在旋转时会返回一个布尔值，它会被您的应用程序调用一次，因此在结束时它可能会返回null.尝试使用a旋转和int temp值.临时使用temp ++进行旋转.记住，每次旋转时都要使用BranchReader.Read()方法；
这是这些查询错误之一.请尝试并返回给我.

When you use BranchReader.Read() in a While rotation it will return a bool value and it will called by your application one time so when it comes to end it can return null.Try to use a for rotation and int temp value.Remember to increase your temp''s value on every rotation with temp++.And remember to use your BranchReader.Read() method on every for rotation''s begining;
This is one of these query mistakes.Try and return to me.

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