Deserializing Data

Problem

You have a DataSet that has been serialized and written to a file. You want to recreate the DataSet from this file.

Solution

Use the serializer object's Deserialize ( ) method and cast the result as a DataSet .

The sample code loads a file stream containing a previously serialized DataSet in a specified format and deserializes it to recreate the original DataSet .

The C# code is shown in Example 5-5.

Example 5-5. File: DeserializeForm.cs

// Namespaces, variables, and constants
using System;
using System.Windows.Forms;
using System.IO;
using System.Data;
using System.Runtime.Serialization;
using System.Runtime.Serialization.Formatters;
using System.Runtime.Serialization.Formatters.Binary;
using System.Runtime.Serialization.Formatters.Soap;
using System.Xml.Serialization;

private OpenFileDialog ofd;

// . . . 

private void goButton_Click(object sender, System.EventArgs e)
{
 // Create and open the stream for deserializing.
 Stream stream = null;
 try
 {
 stream = File.Open(fileNameTextBox.Text, FileMode.Open,
 FileAccess.Read);
 }
 catch(Exception ex)
 {
 MessageBox.Show(ex.Message, "Deserializing Data",
 MessageBoxButtons.OK, MessageBoxIcon.Error);
 return;
 }

 // Deserialize the DataSet from the stream.
 DataSet ds = null;
 try
 {
 if (xmlReadRadioButton.Checked)
 {
 ds = new DataSet( );
 ds.ReadXml(stream);
 }
 else if (xmlSerializerRadioButton.Checked)
 {
 XmlSerializer xs = new XmlSerializer(typeof(DataSet));
 ds = (DataSet)xs.Deserialize(stream);
 }
 else if(soapRadioButton.Checked)
 {
 SoapFormatter sf = new SoapFormatter( );
 ds = (DataSet)sf.Deserialize(stream);
 } 
 else if(binaryRadioButton.Checked)
 {
 BinaryFormatter bf = new BinaryFormatter( );
 ds = (DataSet)bf.Deserialize(stream);
 }
 }
 catch (System.Exception ex)
 {
 MessageBox.Show(ex.Message, "Deserializing Data",
 MessageBoxButtons.OK, MessageBoxIcon.Error);
 return;
 }
 finally
 {
 stream.Close( );
 }

 // Bind the DataSet to the grid.
 dataGrid.DataSource = ds.DefaultViewManager;

 MessageBox.Show("Deserialization complete.", "Deserializing Data",
 MessageBoxButtons.OK, MessageBoxIcon.Information);
}

private void fileDialogButton_Click(object sender, System.EventArgs e)
{
 // File dialog to save file
 if(xmlReadRadioButton.Checked xmlSerializerRadioButton.Checked)
 ofd.Filter = "XML files (*.xml)*.xml";
 else if(soapRadioButton.Checked)
 ofd.Filter = "SOAP files (*.soap)*.soap";
 else if(binaryRadioButton.Checked)
 ofd.Filter = "Binary files (*.bin)*.bin";

 ofd.Filter += "All files (*.*)*.*";
 ofd.FilterIndex = 0;

 if (ofd.ShowDialog( ) == DialogResult.OK)
 fileNameTextBox.Text = ofd.FileName;
}

Discussion

This sample deserializes any of the serialized DataSet objects from Recipe 5.4.

The sample allows the user to select a file and specify a serialization type. The appropriate serializing object is created and in the case of the XmlSerializer object, its type is specified in the constructor. The Deserialize( ) method of the serializer object is then used to deserialize the file stream into an object graph. This is then cast to a DataSet to complete the deserialization.

See the discussion in Recipe 5.4 for more information about the serialization and the formatter classes that can serialize ADO.NET objects.

Connecting to Data

Retrieving and Managing Data

Searching and Analyzing Data

Adding and Modifying Data

Copying and Transferring Data

Maintaining Database Integrity

Binding Data to .NET User Interfaces

Working with XML

Optimizing .NET Data Access

Enumerating and Maintaining Database Objects

Appendix A. Converting from C# to VB Syntax



ADO. NET Cookbook
ADO.NET 3.5 Cookbook (Cookbooks (OReilly))
ISBN: 0596101406
EAN: 2147483647
Year: 2002
Pages: 222
Authors: Bill Hamilton

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