UpdateCommand不起作用？

Question

So I have code that stores an UPDATE query in a string, then I parameter bind the update query and then execute and update it, this is my code:

string query = "UPDATE Users SET first_name = '@firstname' WHERE ID = @id";
updateUserDS.UpdateParameters.Add("id", HTTPContext.Current.Session["ColumnID"].ToString());
updateUserDS.UpdateParameters.Add("firstname", txt_firstname.Text);
updateUserDS.UpdateCommand = query; 
updateUserDS.Update();

However when I change my string query to:

string query = "UPDATE Users SET first_name = 'name' WHERE ID = 44";

It works perfectly and updates my table, so I am guessing its something to do with how I have binded the query, does anyone realise anything where I have gone wrong?

BTW: The Session["ColumnID"] is being retrieved perfectly as it states 44 in the stack trace

Answer 1

Remove the single quotes from @firstname :

string query = "UPDATE Users SET first_name = @firstname WHERE ID = @id";
updateUserDS.Parameters.AddWithValue("@firstname", first_name);
updateUserDS.Parameters.AddWithValue("@id", HTTPContext.Current.Session["ColumnID"].ToString());

EDIT:

Assuming you are using SQL Server as database try like this:

SqlCommand sqlComm = new SqlCommand();
sqlComm.CommandText = @"UPDATE Users SET first_name = @firstname WHERE ID = @id";
sqlComm.Parameters.Add("@firstname", SqlDbType.VarChar);
sqlComm.Parameters["@firstname"].Value = txt_firstname.Text;
sqlComm.Parameters.Add("@id", SqlDbType.VarChar);
sqlComm.Parameters["@id"].Value = HTTPContext.Current.Session["ColumnID"].ToString();    

using (SqlConnection sqlConn = new SqlConnection(connection string here);)
{
    sqlComm.Connection = sqlConn;
    sqlConn.Open();
    sqlComm.ExecuteNonQuery();
}

Answer 2

I'd rewrite this as to use OldDbCommand and OleDbConnection instead of SqlDataSource . It doesn't depend on System.Web assembly (smaller deployment size for non-web situations), there's fewer layers in the stack trace (faster), and it's how most people are used to using ADO.NET.

var command = new OleDbCommand("UPDATE Users SET first_name = ? WHERE ID = ?");
command.Parameters.AddWithValue("id", Session["ColumnID"].ToString());
command.Parameters.AddWithValue("firstname", txt_firstname.Text);

using (var connection = new OleDbConnection(connectionString))
{
    command.Connection = connection;
    connection.Open();
    command.ExecuteNonQuery();
}

---

Another note, you seem to be doing your database access directly in the UI layer! That's hard to test, and not very flexible. It'd be better if you moved all data access code into a separate class library, and then communicate back and forth by passing Models , which are code representations of database entities.

You're also using Access, which isn't really that great of a database system. MS SQL Server is much preferable.

That might look something like this:

Code Behind

DataLayer DB {get; set;}

protected void Page_Load(object sender, EventArgs e)
{
    DB = new DataLayer("connectionstring");
}

protected void SubmitBtn_Click(object sender, EventArgs e)
{
    SystemUser user = new SystemUser()
    {
        Id = Session["ColumnID"].ToString(),
        FirstName = txt_firstname.Text
    }
    DB.UpdateUser(user);
}

Data Layer

public class DataLayer
{
    string ConnectionString {get; set;}

    public DataLayer(string connectionString)
    {
       ConnectionString = connectionString;  
    }

    public void UpdateUser(SystemUser user)
    {
        var command = new SqlCommand("UPDATE Users SET first_name = @firstname WHERE ID = @id");
        command.Parameters.AddWithValue("id", user.Id);
        command.Parameters.AddWithValue("firstname", user.FirstName);

        using (var connection = new SqlConnection(ConnectionString))
        {
            command.Connection = connection;
            connection.Open();
            command.ExecuteNonQuery();
        }
    }

    public void ChangePassword(string UserId, string password)
    {
        //hash and change password here
    }
}

Models

public class SystemUser
{
    public string Id {get; set;}
    public string FirstName {get; set;}
}