Comparing rows with Linq?

[Harvey Saayman]

Hey guys lets say I've got a table in a SQL data base with the fields ID, FirstName, LastName now in my application the user can edit a row in the db. The contents of this table is displayed on a DataGridView and once a row is double clicked another form opens with that particular rows data filled in. Once the data has been edited the user clicks "SAVE" and a stored procedure is called to update the data in the db. now what i need is that after the data has been updated i must know what changed and what are the old and new values. At the moment it works something similar to this

public partial class Form1 : Form
{
int tempId;
string tempFirstName;
string tempLastName;

    public Form1()
    {
        InitializeComponent();

        //
        // Nothing happens here, this constructor is used 
        // when the user wishes to add a new row to the db
        //
    }

    public Form1(int ID)
    {
        InitializeComponent();

        //
        // This constuctor is used when the user wishes to
        // edit a row in the db, so the old values need to
        // be queried and filled into the controles on the form
        //

        //
        // create and Open the sql connection
        string connString = ConfigurationManager.ConnectionStrings\["sqlConnString"\].ConnectionString;
        SqlConnection mySqlConn = new SqlConnection(connString);
        mySqlConn.Open();

        //
        // Initialize the stored procedure
        SqlCommand insertCommand = new SqlCommand("Proc\_SelectPersontByID", mySqlConn);
        insertCommand.CommandType = CommandType.StoredProcedure;

        insertCommand.Parameters.AddWithValue("@ID", ID);

        //
        // Execute the reader
        SqlDataReader reader = insertCommand.ExecuteReader();
        reader.Read();

        //
        // Fill in the initial values
        txtID.Text = reader\["ID"\].ToString();
        txtFirstName.Text = reader\["FirstName"\].ToString();
        txtLastName.Text = reader\["LastName"\].ToString();

        //
        // Now we need to save these values for comparison later
        tempId = reader\["ID"\].ToString();
        tempFirstName = reader\["FirstName"\].ToString();
        tempLastName = reader\["LastName"\].ToString();
    }

    private void btnSave\_Click(object s

[Pete OHanlon]

The DataContext supplies a GetChangeSet method that should help.

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[Harvey Saayman]

Thanx pete ill have a look at it tomorrow morning, i only learnt Linq today :rolleyes:

Harvey Saayman - South Africa Junior Developer .Net, C#, SQL

you.suck = (you.passion != Programming)

[Pete OHanlon]

HarveySaayman wrote:

i only learnt Linq today

Wow, that's quick. I've only been learning it for a year now.

Deja View - the feeling that you've seen this post before.

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[Harvey Saayman]

im no expert... yet :) But i get the basic concept. played around with Linq to objects today and read through Linq to SQL and Linq to XML in "Pro C# 2008 and .Net 3.5 Platform". gona do some practical Linq to SQL tomorow morning before i start implementing it in my project :)

Harvey Saayman - South Africa Junior Developer .Net, C#, SQL

you.suck = (you.passion != Programming)