Interact with CRM form objects from Silverlight through the HTML Bridge

In this post I will show you how we can access attributes on the form via Silverlight managed code.

When you host a Silverlight application in a HTML page you can access the HTML Document Object Model (DOM) from the managed code, and call managed code from JavaScript. This is possible using the HTML Bridge technology available in Silverlight.
In the same way you can access the xrm objects on a Dynamics Crm form using managed code and vice versa when a Silverlight application is embedded in a Crm form.
In this post I will show you a simple example of how to do this.

Recipe for this example:

• I will create a simple Silverlight application
• Create a Silverlight web resource
• Add the web resource to a Crm form
• Verify

The Silverlight application consists of a Textbox and a Button as shown below:

<StackPanel Orientation="Horizontal" VerticalAlignment="Top" HorizontalAlignment="Stretch">
            <TextBox x:Name="InputText" Width="200" Height="23"/>
            <Button Content="Go" Width="22" Height="20" Click="Button_Click" Margin="4,0,0,0"/>
</StackPanel>

After having created the Silverlight application let's add the following code to the Button_Click  event handler:

add this a reference to the "System.Windows.Browser" to your Silverlight project and the using statement in order to be able to use the HTML Bridge,

using System.Windows.Browser;

private void Button_Click(object sender, RoutedEventArgs e)
        {
            //Get the xrm object using the dynamic type
            dynamic xrm = (ScriptObject)HtmlPage.Window.GetProperty("Xrm");
            //this is the number of employees attribute
            var numEmployees = xrm.Page.data.entity.attributes.get("numberofemployees");

            try
            {
               
                if (!string.IsNullOrEmpty(InputText.Text))
                {
                    //convert to int the input from SL text box
                    var employees = Convert.ToInt32(InputText.Text);

                    //set the attribute on the Crm form
                    numEmployees.setValue(employees);
                }
                else
                {
                    //set the attribute on the form
                    numEmployees.setValue(null);
                }
            }
            catch(System.FormatException fe)
            {
                HtmlPage.Window.Alert(string.Format("{0}", fe.Message));
            }
            catch(System.OverflowException ofe)
            {
                HtmlPage.Window.Alert(string.Format("{0}" , ofe.Message));
            }
        }

After having added the Silverlight web resource (see this post) we can now embed it in a form (the account form in this example), thje result is shown below:

To test the application enter a value into the textbox and enter "Go", you should see the number of employee populated with the value you have inserted in alternative you can leave the text box empty.
If you try to enter a value that is too large, too small or is not a number an exception will be thrown and a message will be displayed (see below) . Note that the messages are once again shown using the HTML Bridge through the following lines of code:

HtmlPage.Window.Alert(string.Format("{0}", fe.Message));
HtmlPage.Window.Alert(string.Format("{0}" , ofe.Message));


Alternatively we could have used a Silverlight Child window or simple MessageBox.Show("")

Well that's all really! Next time we will see how to call a Silverlight method from Crm form.

Stay tuned.

Luciano.