Question

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;
using System.Data;

public partial class FormCreationWithDataStoraget : System.Web.UI.Page
{

    protected void Page_Load(object sender, EventArgs e)
    {

    }
    protected void sbmt_Click(object sender, EventArgs e)
    {
        string connectionString = ConfigurationManager.ConnectionStrings["Data Source=RAJIM  -PC;Initial Catalog=RajiDatabase;Integrated Security=True"].ConnectionString;
        string insertSql = "INSERT INTO FamilyDetails(FirstName,LastName,Gender,Age,Relationship,MobileNumber)" + "values(@FirstName,@LaseName,@Gender,,@Age,@,@MobileNumber)";
        SqlConnection conn = new SqlConnection(connectionString);
        SqlCommand scmd = new SqlCommand();
        scmd.Connection = conn;
        scmd.CommandType = CommandType.Text;
        scmd.CommandText = insertSql;

        SqlParameter firstname = new SqlParameter("@FirstName", SqlDbType.VarChar, 40);
        firstname.Value = tbx.Text.ToString();
        scmd.Parameters.Add(firstname);

        SqlParameter lastname = new SqlParameter("@LaseName", SqlDbType.VarChar, 40);
        lastname.Value = tbx1.Text.ToString();
        scmd.Parameters.Add(lastname);

        SqlParameter gender=new SqlParameter("@Gender",SqlDbType.VarChar,40);
        gender.Value = rbt.SelectedItem.ToString();
        scmd.Parameters.Add(gender);

        SqlParameter age = new SqlParameter("@Age", SqlDbType.Int);
        age.Value = tbx2.Text.ToString();
        scmd.Parameters.Add(age);

        SqlParameter relationship = new SqlParameter("@Relationship", SqlDbType.VarChar, 40);
        relationship.Value = tbx3.Text.ToString();
        scmd.Parameters.Add(relationship);

        SqlParameter mobilenumber=new SqlParameter("@MobileNumber",SqlDbType.VarChar, 10);
        mobilenumber.Value = tbx4.Text.ToString();
        scmd.Parameters.Add(mobilenumber);


        try
        {
            conn.Open();
           scmd.ExecuteNonQuery();
           Response.Write("User Registration successful");
        }
        catch (SqlException ex)
        {
            string errorMessage = "Error in registering user";
            errorMessage += ex.Message;
            throw new Exception(errorMessage);

        }
        finally
        {
            conn.Close();
        }
    }

}

Answer 1

看起来这一行导致了您的问题：

string insertSql = "INSERT INTO FamilyDetails(FirstName,LastName,Gender,Age,Relationship,MobileNumber)" + "values(@FirstName,@LaseName,@Gender,,@Age,@,@MobileNumber)";

具体做法是：

@FirstName,@LaseName,@Gender,,@Age,@,@MobileNumber

应该是：

@FirstName,@LaseName,@Gender,@Age,@Relationship,@MobileNumber

Answer 2

问题是这一行：

string connectionString = ConfigurationManager.ConnectionStrings["Data Source=RAJIM  -PC;Initial Catalog=RajiDatabase;Integrated Security=True"].ConnectionString;

没有检索任何对象，因为您没有ConnectionString定义了您的web.config，其名称为＆＃34;数据源= RAJIM ...＆＃34;所以基本上在它结束时调用.ConnectionString会破坏它。

添加＆＃34;数据源= RAJIM ...＆＃34;作为web.config中的连接字符串行（有关连接字符串here的更多信息）。

为连接字符串命名后，即＆＃34; MyConnectionString＆＃34;然后将您的代码更改为：

string connectionString = ConfigurationManager.ConnectionStrings["MyConnectionString"].ConnectionString;

如何解决 - ＆＃34;对象引用未设置为对象的实例＆＃34; C＃出错

2 个答案: