Access Form Data

When you want to extend the functionality of an InfoPath form, it is often necessary to programmatically access information about the form's underlying XML document, access the data that the XML document contains, or perform some action on the XML document. The InfoPath object model supports accessing and manipulating a form's underlying XML document through the use of the XmlForm class in association with the XmlFormCollection class.

The XmlForm class is one of the most useful types in the InfoPath object model because it provides a variety of properties and methods that not only interact with a form's underlying XML document, but also perform many of the actions that are available in the InfoPath user interface.

Overview of the XmlFormCollection Class

The XmlFormCollection class provides the following methods and properties that form developers can use to manage the XmlForm objects that the collection contains.

Overview of the XmlForm Class

The XmlForm class provides the following methods and properties, which form developers can use to interact with and perform actions on a form's underlying XML document.

Using the XmlFormCollection Class

The XmlFormCollection class is accessed through the XmlForms property of the Application class. In a managed code form template created using the object model provided by the members of the Microsoft.Office.InfoPath namespace, you can use the this (C#) or Me (Visual Basic) keyword in your form code to access the Application class and its members.

The following example uses the XmlForms property of the Application class to create an object variable named myForms that references the XDocumentsCollection object of the currently running instance of InfoPath. This variable is then used to display the count of forms that are open.

// Create variable for accessing the XmlFormCollection.
XmlFormCollection myForms = this.Application.XmlForms;
// Display the number of forms that are currently open.
MessageBox.Show("Forms open: " + myForms.Count);

// Create variable for accessing the XmlFormCollection.
Dim myForms As XmlFormCollection = Me.Application.XmlForms
' Display the number of forms that are currently open.
MessageBox.Show("Forms open: " + myForms.Count)

The myForms variable can then also be used to create new forms (using one of the New or NewFromTemplate methods) or open existing forms (using one of the Open methods).

Using the XmlForm Class

In a managed code form template created using the object model provided by the members of the Microsoft.Office.InfoPath namespace, you can use the this (C#) or Me (Visual Basic) keyword in your form code to access the members of the XmlForm class directly (without requiring an object variable that establishes a reference to the XmlForm class).

Accessing a Form's Property Values

The following example uses the this or Me keyword to access the New, ReadOnly, Signed, and Uri properties of the XmlForm class and display the values returned for the current form in a message box.

MessageBox.Show(
   "Is new: " + this.New + System.Environment.NewLine +
   "Is read-only: " + this.ReadOnly + System.Environment.NewLine +
   "Is signed: " + this.Signed + System.Environment.NewLine +
   "Form URI: " + this.Uri);

MessageBox.Show( _
   "Is new: " & Me.New & System.Environment.NewLine & _
   "Is read-only: " & Me.ReadOnly & System.Environment.NewLine + _
   "Is signed: " & Me.Signed & System.Environment.NewLine & _
   "Form URI: " & this.Uri)

Accessing a Form's Data Source

A key property of the XmlForm class with respect to form data is the MainDataSource property. This property returns a reference to a DataSource object that represents the underlying XML data of the current form, which is also referred to as the form's main or primary data source. The DataSource class provides the CreateNavigator method, which creates a XPathNavigator object positioned at the root of the form's underlying XML document. The properties and methods of the XPathNavigator class can then be used to navigate and edit the form's underlying XML data.

The following example uses the MainDataSource property of the XmlForm class to create an XPathNavigator object positioned at the root of the form's main data source. The OuterXml property of the XPathNavigator class is then used to return and display all of the contents of a form's underlying XML document.

// Get outer XML of the underlying XML document.
string myDoc = this.MainDataSource.CreateNavigator.OuterXml.ToString();
// Display XML.
MessageBox.Show(myDoc);

' Get outer XML of the underlying XML document.
Dim myDoc As String myDoc = _
   Me.MainDataSource.CreateNavigator.OuterXml.ToString()
' Display XML.
MessageBox.Show(myDoc)

To learn more about the XPathNavigator class in an InfoPath form template's business logic, see Work with the XPathNavigator and XPathNodeIterator Classes.

Accessing Data About a Form's Form Template File

Information about the form template associated with a form, including the form definition file (.xsf ) and the source XML data that it contains, can also be accessed using the XmlForm class. This information is accessed using the Template property, which returns a reference to a FormTemplate object that represents the form template associated with the current form.

In the following example, the first message box displays some of the data that is available through the Template class, such as its Uniform Resource Identifier (URI) location (using the Uri property), the cache identifier (using the CacheId property) and its version number (using the Version property). The next message box uses the Manifest property of the Template class to create an XPathNavigator object that is used to display the source XML of the form definition file (.xsf).

// Display form template properties.
MessageBox.Show(
   "Cache ID: " + this.Template.CacheId + System.Environment.NewLine +
   "URI: " + this.ReadOnly + System.Environment.NewLine +
   "Version: " + this.Signed, "Form Template Properties");
// Display form definition file XML.
MessageBox.Show(this.Template.Manifest.OuterXml, 
   "Form Definition File XML");

' Display form template properties.
MessageBox.Show( _
   "Cache ID: " & Me.Template.CacheId & System.Environment.NewLine &
   "URI: " & Me.ReadOnly & System.Environment.NewLine &
   "Version: " & Me.Signed, "Form Template Properties")
' Display form definition file XML.
MessageBox.Show(Me.Template.Manifest.OuterXml, _
   "Form Definition File XML")