Copying Rows from One DataTable to Another

[ Team LiB ]Recipe 5.1 Copying Rows from One DataTable to Another Problem You have records in a DataTable that you need to copy to another DataTable.. Three techniques for selecting re

[ Team LiB ]

Recipe 5.1 Copying Rows from One DataTable to Another

Problem

You have records in a DataTable that you need to copy to another DataTable

Solution

Use the ImportRow( ) method of the DataTable to copy DataRow objects from one

DataTable to another Three techniques for selecting records to copy are demonstrated in the following example:

• Use the Rows property to access rows in the DataRowCollection of the DataTable using the row index

• Use the Select( ) method of the DataTable

• Use the RowFilter property of a DataView for the DataTable

The sample code creates a source DataTable containing the Orders table from Northwind

A second empty target DataTable is created with the same schema One of the three techniques, as specified by the user, is used to copy records from the source table to the target table

The C# code is shown in Example 5-1

Example 5-1 File: CopyRowsBetweenTablesForm.cs

// Namespaces, variables, and constants

using System;

using System.Configuration;

using System.Data;

using System.Data.SqlClient;

// Table name constants

private const String ORDERS_TABLE = "Orders";

// Field name constants

private const String ORDERID_FIELD = "OrderID";

//

// Fill the source table with schema and data

SqlDataAdapter da = new SqlDataAdapter("SELECT * FROM Orders",

ConfigurationSettings.AppSettings["Sql_ConnectString"]);

DataTable dt = new DataTable(ORDERS_TABLE);

da.FillSchema(dt, SchemaType.Source);

da.Fill(dt);

// Clone the schema to the copy table

DataTable dtCopy = dt.Clone( );

if(rowRadioButton.Checked)

{

// Use ImportRow method to import the first three rows

for (int i = 0; i < 3; i++)

{

dtCopy.ImportRow(dt.Rows[i]);

}

}

else if (selectRadioButton.Checked)

{

// Copy using result of Select( ) method

foreach(DataRow row in dt.Select(ORDERID_FIELD + " <= 10300"))

{

dtCopy.ImportRow(row);

}

}

else if (filteredDataViewRadioButton.Checked)

{

// Copy using result of filtered DataView

DataView categoryView = dt.DefaultView;

categoryView.RowFilter = ORDERID_FIELD + " >= 10300 AND " +

ORDERID_FIELD + " < 10400";

for (int i = 0; i < categoryView.Count; i++)

{

dtCopy.ImportRow(categoryView[i].Row);

}

}

// Bind the default view of the copy table to the grid

dataGrid.DataSource = dtCopy.DefaultView;

Discussion

Rows can be copied between tables using the ImportRow( ) methods of the DataTable

object The ImportRow( ) method requires that both the source and destination table have the same structure In this example, the Clone( ) method of the DataTable creates a table with identical structure, but any technique that creates a table with an identical structure can be used

Additionally, the Copy( ) method of the DataTable object can create a new DataTable having the same structure and data as the original as shown in the following code sample: // Create the source table

DataTable dtSource = new DataTable("Source");

// Fill the source table with data

// Create the destination table and copy the source table

DataTable dtDest = new DataTable("Dest");

dtDest = dtSource.Copy( );

[ Team LiB ]