C＃ASP.net将数据更新到SQL服务器数据库：作业 [英] C# ASP.net Update Data into a SQL server database : Homework

问题描述

我的作业分配有问题。

我能够访问数据库并插入新客户但是当我尝试更新任何记录时它不起作用。

如果有人能告诉我我的代码有什么问题。

非常感谢



这是我的全部代码



< big> //这是我的问题//

Hi, I have a problem with my homework assignment.
I am able to access the database and insert new customer but it doesn''t work when i try to update any record.
if anyone can tell me what is wrong with my code.
thank you so much

this is all my code

//this is my problem//

protected void btnUpdate_Click(object sender, EventArgs e)
    {

        if (Request.QueryString["MODE"] != null)
        {
          
            
        

          
          //int CustomerID = Convert.ToInt32(Request.QueryString["id"]);

             

            //Declare the connection object
            SqlConnection Conn = new SqlConnection(ConfigurationManager.ConnectionStrings["MyLocal"].ConnectionString);

            //Make the connection 
            Conn.Open();

            //Define you query
            //  string updateSQL = "UPDATE [dbo].[xSample]" + "  " + "Set Region = " + txtFirstName.Text + " " + "SalesID= 1000";                                  
            // string sql = "UPDATE [dbo].[Customer] SET [FirstName] = @FirstName   WHERE CustomerID=@CustomerID";
            string sql = "UPDATE [Customer] SET [FirstName] = @FirstName,  [LastName] = @LastName, [Email] = @Email, [Password] = @Password, [Address1] = @Address1, [Address2] = @Address2, [City] = @City, [State] = @State, [zip] = @zip, [Phone] = @Phone, [Fax] = @Fax  WHERE CustomerID=@CustomerID";
     
            
            //Declare the Command
            SqlCommand cmd = new SqlCommand(sql, Conn);

            //Add the parameters needed for the SQL query
            cmd.Parameters.AddWithValue("@CustomerID", Customer_ID());
            cmd.Parameters.AddWithValue("@FirstName", txtFirstName.Text);
            cmd.Parameters.AddWithValue("@LastName", txtLastName.Text);
            cmd.Parameters.AddWithValue("@Email", txtEmailA.Text);
            cmd.Parameters.AddWithValue("@Password", txtPasswordA.Text);
            cmd.Parameters.AddWithValue("@Address1", txtAddress1.Text);
            cmd.Parameters.AddWithValue("@Address2", txtAddress2.Text);
            cmd.Parameters.AddWithValue("@City", txtCity.Text);
            cmd.Parameters.AddWithValue("@State", txtState.Text);
            cmd.Parameters.AddWithValue("@Zip", txtZip.Text);
            cmd.Parameters.AddWithValue("@Phone", txtPhone.Text);
            cmd.Parameters.AddWithValue("@Fax", txtFax.Text);
                        
            //Execute the query

            cmd.ExecuteNonQuery();

            Conn.Close();
            Response.Redirect("Customers.aspx");
            
            
        }

        

        if (Request.QueryString["id"] == null)
        {
            //Declare the connection object
            SqlConnection Conn = new SqlConnection(ConfigurationManager.ConnectionStrings["MyLocal"].ConnectionString);

            //Make the connection 
            Conn.Open();

            //Define you query
            //string sql = "UPDATE [db_owner].[Customer] SET FirstName=@FirstName, LastName=@LastName, Email=@Email, Password=@Password, Address1=@Address1, Address2=@Address2, City=@City, State=@State, Zip=@Zip, Phone=@Phone, Fax=@Fax  Where CustomerID=@CustomerID";
            string sql = "INSERT INTO Customer(FirstName, LastName, Email, Password, Address1, Address2, City, State, Zip, Phone, Fax) VALUES(@FirstName, @LastName, @Email, @Password, @Address1, @Address2, @City, @State, @Zip, @Phone, @Fax)";
            //string sqlN = "INSERT INTO [Customer] ([FirstName], [LastName], [Email], [Password], [Address1], [Address2], [City], [State], [Zip], [Phone], [Fax]) VALUES (@FirstName, @LastName, @Email, @Password, @Address1, @Address2, @City, @State, @Zip, @Phone, @Fax)";
            //Declare the Command
            SqlCommand cmd = new SqlCommand(sql, Conn);

            //Add the parameters needed for the SQL query

            cmd.Parameters.AddWithValue("@FirstName", txtFirstName.Text);
            cmd.Parameters.AddWithValue("@LastName", txtLastName.Text);
            cmd.Parameters.AddWithValue("@Email", txtEmailA.Text);
            cmd.Parameters.AddWithValue("@Password", txtPasswordA.Text);
            cmd.Parameters.AddWithValue("@Address1", txtAddress1.Text);
            cmd.Parameters.AddWithValue("@Address2", txtAddress2.Text);
            cmd.Parameters.AddWithValue("@City", txtCity.Text);
            cmd.Parameters.AddWithValue("@State", txtState.Text);
            cmd.Parameters.AddWithValue("@Zip", txtZip.Text);
            cmd.Parameters.AddWithValue("@Phone", txtPhone.Text);
            cmd.Parameters.AddWithValue("@Fax", txtFax.Text);



            //Execute the query

            cmd.ExecuteNonQuery();

            Conn.Close();
            Response.Redirect("Customers.aspx");

        }
          
    }

此代码中的问题不在更新中。任何人都可以告诉我它有什么问题

the problem in this code not in the update. anyone can tell me what is wrong with it

public int Customer_ID()

{
    int CustomerID = 0;
   CustomerID= int.Parse(Request.QueryString["id"]);

  return CustomerID;

}





protected void Page_Load(object sender, EventArgs e)
{
   this.Master.HighlightMenu = "Customers";

   // if (Request.QueryString["MODE"] != null)
   // {
    if (Customer_ID()!=0)
    {


                txtFirstName.Text = "";
                txtLastName.Text = "";
                txtEmailA.Text = "";
                txtEmailB.Text = "";
                txtCity.Text = "";
                txtPasswordA.Text = "";
                txtPasswordB.Text = "";
                txtFax.Text = "";
                txtAddress1.Text = "";
                txtAddress2.Text = "";
                txtState.Text = "";
                txtZip.Text = "";
                txtPhone.Text = "";


        //Declare the connection object
        SqlConnection Conn = new SqlConnection(ConfigurationManager.ConnectionStrings["MyLocal"].ConnectionString);

        //Make the connection
        Conn.Open();

        //Define you query
        string sql = "SELECT * FROM [db_owner].[Customer] Where CustomerID=@CustomerID";

        //Declare the Command
        SqlCommand cmd = new SqlCommand(sql, Conn);

        //Add the parameters needed for the SQL query
        cmd.Parameters.AddWithValue("@CustomerID", Customer_ID());

        //Declare the DataReader
        SqlDataReader dr = null;

        //Fill the DataReader
        dr = cmd.ExecuteReader();

        //Get the data
        if (dr.Read() == false)
        {
            //No Records
            dr.Close();
            Conn.Close();
            return;
        }
        txtFirstName.Text = dr["FirstName"].ToString();
        txtLastName.Text = dr["LastName"].ToString();
        txtEmailA.Text = dr["Email"].ToString();
        txtEmailB.Text = dr["Email"].ToString();

        txtPasswordA.Text = dr["Password"].ToString();
        txtPasswordB.Text = dr["Password"].ToString();
        txtAddress1.Text = dr["Address1"].ToString();
        txtAddress2.Text = dr["Address2"].ToString();
        txtCity.Text = dr["City"].ToString();
        txtState.Text = dr["State"].ToString();
        txtZip.Text = dr["Zip"].ToString();
        txtFax.Text = dr["Fax"].ToString();
        txtPhone.Text = dr["Phone"].ToString();


        dr.Close();
        Conn.Close();
    }
}

推荐答案

我的问题是我忘了把回传放在页面上加载。





if（！IsPostBack）

{

my problem was i forgot to put postback in when the page load.


if (!IsPostBack)
{

cmd.Parameters.AddWithValue("@CustomerID", CustomerID);

您在哪里设置CustomerID？如果没有设置它将始终为0并且WHERE子句将不匹配任何记录。



您还应该学习使用语句

Where are you setting CustomerID? If it is not set it will always be 0 and the WHERE clause will not match any record.

You should also learn about using statements

using(SqlConnection conn = new SqlConnection(...))
{

}

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