C# Parameter.addwithvalue - ExecuteReader：CommandText 属性尚未初始化
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Parameter.addwithvalue - ExecuteReader: CommandText property has not been initialized
提问by user1339253
I get the error ExecuteReader: CommandText property has not been initializedat the adapter.fill(ds)line. The weird thing is that if I replace @userwith an actual string (e.g. 'name') it works perfectly fine, so something seems to be broken in the part that sets the parameter.
我收到错误ExecuteReader: CommandText property has not been initializedat the adapter.fill(ds)line。奇怪的是，如果我@user用实际的字符串（例如“名称”）替换它，它就可以正常工作，因此设置参数的部分似乎有问题。
I've tried to set the string both with and without ''s (i.e. @user/'@user'). I've also tried using both =and like. User.Identity.Name.ToString()has been tested to return the logged in user correctly by setting a textbox to it.
我试图设置带有和不带有'' 的字符串（即@user/'@user'）。我也试过同时使用=和like。User.Identity.Name.ToString()已经过测试，可以通过设置文本框来正确返回登录用户。
Sorry for the non-English database variables and if this question has been answered somewhere. I've almost given up after half a dozen hours of searching, though (maybe I just suck at it).
抱歉非英语数据库变量以及此问题是否已在某处得到解答。不过，经过六个小时的搜索，我几乎放弃了（也许我只是很烂）。
Relevant code:
相关代码：
using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Configuration;
using System.Data;
using System.Data.SqlClient;
public partial class Bruker : System.Web.UI.Page
{
protected void Page_Load(object sender, EventArgs e)
{
String conn = ConfigurationManager.ConnectionStrings["LocalSqlServer"].ConnectionString;
SqlConnection sql = new SqlConnection(conn);
sql.Open();
SqlCommand command = new SqlCommand(conn);
command.CommandText = "SELECT klubb.KlubbNavn FROM Klubber klubb inner join User_Klubber_Connection conn on Klubb.Klubb_Id = conn.Klubb_Id inner join aspnet_Users bruker on bruker.UserId = conn.UserId WHERE bruker.UserName = @user";
command.Parameters.AddWithValue("@user", User.Identity.Name.ToString());
command.Connection = sql;
SetDropDownList(command);
DropDownList1.SelectedIndex = 0;
ChangeGridView(GetMembersOfClub(), sql);
sql.Close();
}
protected void SetDropDownList(SqlCommand command)
{
SqlDataAdapter adapter = new SqlDataAdapter(command);
SqlCommandBuilder builder = new SqlCommandBuilder(adapter);
DataSet ds = new DataSet();
adapter.Fill(ds);
DropDownList1.DataSource = ds;
DropDownList1.DataTextField = "KlubbNavn";
DropDownList1.DataBind();
}
}
采纳答案by Siz S
EditForget everything just do following on page_load
编辑忘记一切，只需在 page_load 上执行以下操作
Response.Write(String.Format("user name is {0}", User.Identity.Name));
And see the output
并查看输出
its running fine
它运行良好
protected void Page_Load(object sender, EventArgs e)
{
SqlConnection sql = new SqlConnection( ConfigurationManager.ConnectionStrings["yourConnectionName"].ConnectionString);
sql.Open();
SqlCommand command = new SqlCommand("Select * from userinfo where uloginid=@user", sql);
command.Parameters.AddWithValue("@user", User.Identity.Name.ToString());
SetDropDownList(command);
DropDownList1.SelectedIndex = 0;
sql.Close();
}
protected void SetDropDownList(SqlCommand command)
{
SqlDataAdapter adapter = new SqlDataAdapter(command);
SqlCommandBuilder builder = new SqlCommandBuilder(adapter);
DataSet ds = new DataSet();
adapter.Fill(ds);
DropDownList1.DataSource = ds;
DropDownList1.DataTextField = "uFirstName";
DropDownList1.DataBind();
}
回答by Retired_User
Probably you're getting nullin command.Parameters.AddWithValue("@user", User.Identity.Name.ToString());
也许你得到null的command.Parameters.AddWithValue("@user", User.Identity.Name.ToString());
Try:
尝试：
command.Parameters.AddWithValue("@user", User.Identity.Name ?? String.Empty);
Edit: (after comments)
编辑：（评论后）
Have you tried to create a parameter manually?
您是否尝试过手动创建参数？
Instead of using AddWithValue(...)try :
而不是使用AddWithValue(...)try ：
SqlParameter param = new SqlParameter();
param.ParameterName = "@user";
param.Value = User.Identity.Name.ToString();
param.DbType = SqlDbType.VarChar;
command.Parameters.Add(param);
