ADO.NET DataRows

The DataRow object represents a single row of data within a DataTable. It provides access to the values in each column for that specific row.

Key Concepts

Accessing Column Values

You can access the value of a specific column in a DataRow by using the column's name or its ordinal position (index). It's recommended to use the column name for better readability and maintainability.

// Assuming 'row' is a DataRow and 'dt' is its DataTable
string customerName = row["CustomerName"].ToString();
int customerId = (int)row[0]; // Accessing by ordinal position
        

Modifying DataRow Values

You can modify the values in a DataRow before adding it to a DataTable or updating an existing row.

row["CustomerName"] = "New Customer Name";
row[1] = 12345; // Modifying by ordinal position
        

Row States

Each DataRow has a RowState property that indicates its current status. This is crucial when working with changes and submitting them to a data source.

• DataRowState.Unchanged: The row has not been modified since it was loaded or accepted changes.
• DataRowState.Added: The row has been added to the DataTable but its changes have not yet been accepted.
• DataRowState.Modified: The row has been changed since it was loaded or its changes were last accepted.
• DataRowState.Deleted: The row has been marked for deletion.
• DataRowState.Detached: The row is not currently associated with a DataTable.

Row Versioning

DataRow supports row versioning, allowing you to access the original and current versions of a row's data. This is useful for implementing optimistic concurrency.

• DataRowVersion.Current: The most recent version of the row.
• DataRowVersion.Original: The version of the row before any modifications were made since it was loaded or changes were last accepted.
• DataRowVersion.Proposed: The version of the row with proposed changes, typically before AcceptChanges() is called.

// Accessing original value
string originalName = row["CustomerName", DataRowVersion.Original].ToString();
        

Handling Null Values

When a database column can contain null values, ADO.NET represents them using DBNull.Value. You should check for this value before attempting to use a column's value.

if (row["Email"] != DBNull.Value)
{
    string email = row["Email"].ToString();
    // Process email
}
else
{
    // Email is null
}
        

Common Operations

Iterating Through Rows

You can iterate through the rows of a DataTable using a foreach loop.

DataTable customersTable = dataSet.Tables["Customers"];
foreach (DataRow row in customersTable.Rows)
{
    Console.WriteLine($"Customer ID: {row["CustomerID"]}, Name: {row["Name"]}");
}
        

Finding Rows

The Select() method on a DataTable can be used to filter rows based on a filter expression.

DataRow[] foundRows = customersTable.Select("City = 'London'");
foreach (DataRow row in foundRows)
{
    Console.WriteLine($"Found: {row["Name"]}");
}
        

API Reference Highlights

Related Topics

• ADO.NET DataTable
• ADO.NET DataSet
• ADO.NET DataColumns