Read XML data into a dataset

ADO.NET provides simple methods for working with XML data. In this walkthrough, you create a Windows application that loads XML data into a dataset. The dataset is then displayed in a DataGridView control. Finally, an XML schema based on the contents of the XML file is displayed in a text box.

This walkthrough consists of five main steps:

1. Creating a new project

2. Creating an XML file to be read into the dataset

3. Creating the user interface

4. Creating the dataset, reading the XML file, and displaying it in a DataGridView control

5. Adding code to display the XML schema based on the XML file in a TextBox control

Create a new project

In this step, you create a Visual Basic or Visual C# project that contains this walkthrough.

To create the new Windows project

1. On the File menu, create a new project.

2. Name the project ReadingXML.

3. Select Windows Application, and then select OK. For more information, see Client Applications.

   The ReadingXML project is created and added to Solution Explorer.

Generate the XML file to be read into the dataset

Because this walkthrough focuses on reading XML data into a dataset, the contents of an XML file is provided.

To create the XML file that will be read into the dataset

1. On the Project menu, selectAdd New Item.

2. Select XML File, name the file authors.xml, and then select Add.

   The XML file loads into the designer and is ready for edit.

3. Paste the following code into the editor below the XML declaration:

   <Authors_Table>
     <authors>
       <au_id>172-32-1176</au_id>
       <au_lname>White</au_lname>
       <au_fname>Johnson</au_fname>
       <phone>408 496-7223</phone>
       <address>10932 Bigge Rd.</address>
       <city>Menlo Park</city>
       <state>CA</state>
       <zip>94025</zip>
       <contract>true</contract>
     </authors>
     <authors>
       <au_id>213-46-8915</au_id>
       <au_lname>Green</au_lname>
       <au_fname>Margie</au_fname>
       <phone>415 986-7020</phone>
       <address>309 63rd St. #411</address>
       <city>Oakland</city>
       <state>CA</state>
       <zip>94618</zip>
       <contract>true</contract>
     </authors>
     <authors>
       <au_id>238-95-7766</au_id>
       <au_lname>Carson</au_lname>
       <au_fname>Cheryl</au_fname>
       <phone>415 548-7723</phone>
       <address>589 Darwin Ln.</address>
       <city>Berkeley</city>
       <state>CA</state>
       <zip>94705</zip>
       <contract>true</contract>
     </authors>
     <authors>
       <au_id>267-41-2394</au_id>
       <au_lname>Hunter</au_lname>
       <au_fname>Anne</au_fname>
       <phone>408 286-2428</phone>
       <address>22 Cleveland Av. #14</address>
       <city>San Jose</city>
       <state>CA</state>
       <zip>95128</zip>
       <contract>true</contract>
     </authors>
     <authors>
       <au_id>274-80-9391</au_id>
       <au_lname>Straight</au_lname>
       <au_fname>Dean</au_fname>
       <phone>415 834-2919</phone>
       <address>5420 College Av.</address>
       <city>Oakland</city>
       <state>CA</state>
       <zip>94609</zip>
       <contract>true</contract>
     </authors>
   </Authors_Table>
   

4. On the File menu, selectSave authors.xml.

Create the user interface

The user interface for this application consists of the following:

• A DataGridView control that displays the contents of the XML file as data.

• A TextBox control that displays the XML schema for the XML file.

• Two Button controls.

  • One button reads the XML file into the dataset and displays it in the DataGridView control.

  • A second button extracts the schema from the dataset, and through a StringWriter displays it in the TextBox control.

To add controls to the form

1. Open Form1 in design view.

2. From the Toolbox, drag the following controls onto the form:

   • One DataGridView control

   • One TextBox control

   • Two Button controls

3. Set the following properties:

   Control	Property	Setting
   TextBox1	Multiline	true
   	ScrollBars	Vertical
   Button1	Name	ReadXmlButton
   	Text	Read XML
   Button2	Name	ShowSchemaButton
   	Text	Show Schema

Create the dataset thatreceives the XML data

In this step, you create a new dataset named authors. For more information about datasets, see Dataset tools in Visual Studio.

To create a new dataset that receives the XML data

1. In Solution Explorer, select the source file for Form1, and then select the View Designer button on the Solution Explorer toolbar.

2. From the Toolbox, Data Tab, drag a DataSet onto Form1.

3. In the Add Dataset dialog box, select Untyped dataset, and then select OK.

   DataSet1 is added to the component tray.

4. In the Properties window, set the Name and DataSetName properties forAuthorsDataSet.

Create the event handler to read the XML file into the dataset

The Read XML button reads the XML file into the dataset. It then sets properties on the DataGridView control that bind it to the dataset.

To add code to the ReadXmlButton_Click event handler

1. In Solution Explorer, select Form1, and then select the View Designer button on the Solution Explorer toolbar.

2. Select the Read XML button.

   The Code Editor opens at the ReadXmlButton_Click event handler.

3. Type the following code into the ReadXmlButton_Click event handler:

   private void ReadXmlButton_Click(object sender, EventArgs e)
   {
       string filePath = "Complete path where you saved the XML file";
   
       AuthorsDataSet.ReadXml(filePath);
   
       dataGridView1.DataSource = AuthorsDataSet;
       dataGridView1.DataMember = "authors";
   }
   

   Private Sub ReadXmlButton_Click() Handles ReadXmlButton.Click
   
       Dim filePath As String = "Complete path where you saved the XML file"
   
       AuthorsDataSet.ReadXml(filePath)
   
       DataGridView1.DataSource = AuthorsDataSet
       DataGridView1.DataMember = "authors"
   End Sub
   

4. In the ReadXMLButton_Click event handler code, change the filepath = entry to the correct path.

Create the event handler to display the schema in the textbox

The Show Schema button creates a StringWriter object that's filled with the schema and is displayed in the TextBoxcontrol.

To add code to the ShowSchemaButton_Click event handler

1. In Solution Explorer, select Form1, and then select the View Designer button.

2. Select the Show Schema button.

   The Code Editor opens at the ShowSchemaButton_Click event handler.

3. Type the following code into the ShowSchemaButton_Click event handler.

   private void ShowSchemaButton_Click(object sender, EventArgs e)
   {
       System.IO.StringWriter swXML = new System.IO.StringWriter();
       AuthorsDataSet.WriteXmlSchema(swXML);
       textBox1.Text = swXML.ToString();
   }
   

   Private Sub ShowSchemaButton_Click() Handles ShowSchemaButton.Click
   
       Dim swXML As New System.IO.StringWriter()
       AuthorsDataSet.WriteXmlSchema(swXML)
       TextBox1.Text = swXML.ToString
   End Sub
   

Test the form

You can now test the form to make sure it behaves as expected.

1. Select F5 to run the application.

2. Select the Read XML button.

   The DataGridView displays the contents of the XML file.

3. Select the Show Schema button.

   The text box displays the XML schema for the XML file.

Next Steps

This walkthrough teaches you the basics of reading an XML file into a dataset, as well as creating a schema based on the contents of the XML file. Here are some tasks that you might do next:

• Edit the data in the dataset and write it back out as XML. For more information, see WriteXml.

• Edit the data in the dataset and write it out to a database.

See Also

Data Walkthroughs Accessing data in Visual Studio Preparing Your Application to Receive Data XML Tools in Visual Studio