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即时通讯相当新,但我熟悉空引用异常,但我无法解决这一问题。我试图从webform收集数据,并通过连接字符串传递给我的数据库,这是发生异常的时候。NullReferenceException我很熟悉它们,但在这种情况下不能解决
using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Data.SqlClient;
using System.Configuration;
public partial class Register : System.Web.UI.Page
{
protected void Page_Load(object sender, EventArgs e)
{
try
{
if (IsPostBack)
{
SqlConnection studConnA = new SqlConnection(ConfigurationManager.ConnectionStrings["StudConnection"].ConnectionString);
studConnA.Open();
string checkuser = "select count(*) from StudTable where Name='" + TextBoxName.Text + "'";
SqlCommand studComA = new SqlCommand(checkuser, studConnA);
int temp = Convert.ToInt32(studComA.ExecuteScalar().ToString());
if (temp == 1)
{
Response.Write("User already Exists");
}
studConnA.Close();
}
}
catch (Exception ex)
{
Response.Write("Error:" + ex.ToString());
}
}
protected void Button1_Click(object sender, System.EventArgs e)
{
try
{
SqlConnection studConn = new SqlConnection(ConfigurationManager.ConnectionStrings["StudConnectionString"].ConnectionString);
studConn.Open();
string insertQuery = "insert into StudTable (Name,Email,Age,Continent,School,Password) values (@name,@email,@age,@cont,@school,@pass)";
SqlCommand studCom = new SqlCommand(insertQuery, studConn);
studCom.Parameters.AddWithValue("@name", TextBoxName.Text);
studCom.Parameters.AddWithValue("@email", TextBoxEmail.Text);
studCom.Parameters.AddWithValue("@age", TextBoxAge.Text);
studCom.Parameters.AddWithValue("@cont",DropDownCont.SelectedItem.ToString());
studCom.Parameters.AddWithValue("@school", TextBoxSchool.Text);
studCom.Parameters.AddWithValue("@pas", TextBoxPass.Text);
studCom.ExecuteNonQuery();
Response.Redirect("Backend.aspx");
Response.Write("Your Registration is Sucessful");
studConn.Close();
}
catch (Exception ex)
{
Response.Write("Error:" +ex.ToString());
}
}
}
空引用发生在第19行
Line 17: if (IsPostBack)
Line 18: {
Line 19: SqlConnection studConnA = new SqlConnection(ConfigurationManager.ConnectionStrings["StudConnection"].ConnectionString);
Line 20: studConnA.Open();
Line 21: string checkuser = "select count(*) from StudTable where Name='" + TextBoxName.Text + "'";
我相信这个问题是我的连接字符串,但林不知道,
谁能帮我解决这个语法?
那么它听起来像你没有叫'StudConnection'连接字符串 - 但即使你已经固定的,你应该*还*参数化您的SQL,而不是像现在一样直接将值包括在内。 –
这个nullref与其他的一样。您已经取消了空引用。点之前的一件事是空的。可能是'ConfigurationManager.ConnectionStrings [“StudConnection”]'。 – usr
感谢您的帮助,我以某种方式导入了错误的web.config,但现在解决了它! – Erademus