Workflow Context always null

Question

I am a newbie in the custom workflow development. The scenario I want to send an email notification to the group when an item is created in the list. I am referring to http://davesquared.net/2007/07/sending-email-to-group-with-sharepoint.html Depending on the above explanation I wrote the below code, however the _Context object is always null "var _NameToEmailResolver = new NameToEmailResolver(_Context);"

Any thoughts on why _Context is null, and how to get the workflow context. below is the code which i implemented. is it required to have more than 1 dependency property to achieve below functionality. Will appreciate if any one helps with this.

public sealed partial class Workflow1 : SequentialWorkflowActivity
{
    public Workflow1()
    {
        InitializeComponent();
    }

    public Guid workflowId = default(System.Guid);
    public SPWorkflowActivationProperties workflowProperties = new SPWorkflowActivationProperties();
    public static DependencyProperty _ContextProperty = DependencyProperty.Register("_Context", typeof(WorkflowContext), typeof(Workflow1));
    public WorkflowContext _Context
    {
        get
        {
            return (WorkflowContext)base.GetValue(_ContextProperty);
        }
        set
        {
            base.SetValue(_ContextProperty, value);
        }
    }

    private void createEmailMessage_ExecuteCode(object sender, EventArgs e)
    {

        var _NameToEmailResolver = new NameToEmailResolver(_Context);

        string _Group = workflowProperties.Item["Assignee"].ToString();
       _Group=_Group.Split(new char[] { ';' })[1].Remove(0,1);
        this.sendAutomatedEmail.To = _NameToEmailResolver.GetEmailAddressesFromName(_Group);
        this.sendAutomatedEmail.From = "donotreplay.com";
        this.sendAutomatedEmail.Body = "Title :" + workflowProperties.Item["Title"];
    }
} 

Answer 1

You may need to pass in the context parameter in the .ACTIONS file, add the following to the <parameters> section:

<Parameter Direction="In" Type="Microsoft.SharePoint.WorkflowActions.WorkflowContext, Microsoft.SharePoint.WorkflowActions" Name="__Context" />

See http://davesquared.net/2007/07/sharepoint-aware-workflow-activities.html for details.

Answer 2

You might need the ApplyActivation activity in the designer in Visual Studio.

Set the __Context to your WorkflowContext _Context property and the __WorkflowProperties to workflowProperties field.

This initialises the context. http://msdn.microsoft.com/en-gb/library/microsoft.sharepoint.workflowactions.applyactivation.aspx

http://social.technet.microsoft.com/forums/en-US/sharepointdevelopmentprevious/thread/e7236d96-133a-42fa-8227-dabb4a70d767