DataRow Class

The DataRow class represents a single row of data within a DataTable. It is a fundamental building block for working with data in ADO.NET, allowing you to access, manipulate, and manage individual records.

Each DataRow object holds the values for a specific record, with each value corresponding to a DataColumn in the parent DataTable.

Key Features and Properties

Accessing Data

You can access the data within a DataRow using several methods:

By Column Name: Using the indexer with the column name (string).
By Column Index: Using the indexer with the column ordinal (integer).
Item(DataColumn): Using the Item property with a DataColumn object.

Example: Accessing Row Data


DataTable customersTable = new DataTable("Customers");
customersTable.Columns.Add("CustomerID", typeof(int));
customersTable.Columns.Add("CompanyName", typeof(string));
customersTable.Columns.Add("ContactName", typeof(string));

// Add a new row
DataRow newRow = customersTable.NewRow();
newRow["CustomerID"] = 1;
newRow["CompanyName"] = "Exotic Liquids";
newRow["ContactName"] = "Charlotte Cooper";
customersTable.Rows.Add(newRow);

// Accessing data from an existing row
DataRow firstRow = customersTable.Rows[0];
int id = (int)firstRow["CustomerID"]; // Access by column name
string company = firstRow[1].ToString(); // Access by column index
string contact = firstRow.Field<string>("ContactName"); // Using Field extensions

Console.WriteLine($"ID: {id}, Company: {company}, Contact: {contact}");

Row State

A DataRow has a state that indicates its current status within the DataTable. This state is crucial when dealing with changes and updates:

Added: The row has been added to the DataTable but not yet accepted.
Modified: The row has been changed since it was loaded or its changes were last accepted.
Deleted: The row has been deleted and its changes accepted.
Unchanged: The row has not been modified since it was loaded or its changes were last accepted.

You can check the row state using the RowState property.

Accessing Original and Current Values

When a row is modified, it retains both its original values and its current (modified) values. You can access these using the OriginalRow property or by specifying the DataRowVersion when accessing data:

DataRowVersion.Current: The current values of the row.
DataRowVersion.Original: The original values of the row.
DataRowVersion.Proposed: The values being proposed for a new row or updated row.

Example: Accessing Original and Current Values


// Assume 'row' is a DataRow that has been modified
Console.WriteLine($"Current Company Name: {row["CompanyName"]}");
Console.WriteLine($"Original Company Name: {row["CompanyName", DataRowVersion.Original]}");

// To get the entire original row
DataRow originalRow = row.Table.Rows.Find(row["CustomerID"]); // Or other primary key lookup
if (originalRow != null) {
    Console.WriteLine($"Original Contact Name: {originalRow["ContactName"]}");
}

Row Error Information

DataRow provides properties for managing row-level errors:

RowError: A general error message for the entire row.
HasErrors: A boolean indicating if the row has any errors.

Modifying Row Data

You can directly assign new values to the DataRow using its indexer:


// Assume 'row' is an existing DataRow
row["ContactName"] = "Janet Flowers";
row["Email"] = "janet.flowers@example.com"; // If 'Email' column exists
row.AcceptChanges(); // To mark the row as unchanged

Deleting Rows

To delete a row, call the Delete() method:


// Assuming 'rowToDelete' is the DataRow to be deleted
rowToDelete.Delete();
// Changes are staged. Call table.AcceptChanges() to finalize deletion.