Sharepoint 2010 Connectable webparts

 This post describes how to create connectable webparts in Sharepoint 2010

A webpart that provides a string and another webpart that consumes and displays the value of the string.
These are the tasks to be followed :

1. Creating an interface to define the string that is being provided.
2. Creating a webpart from Visual Studio Webpart item template
3. Creating a provider webpart that defines a string
4. Creating a consumer webpart that uses and displays a string
5. Creating a webpart page and connecting the provider and consumer webpart.


A)  Creating an empty sharepoint project :

1. Start Visual Studio 2010 in administrator mode.
2. On the File menu, point to New, and then click Project. If Visual Studio is set to use Visual Basic development settings, on the File menu, click New Project.
3. In the New Project dialog box, expand the SharePoint node under the language that you want to use, and then select the 2010 node.
4. In the Templates pane, select Empty SharePoint Project.
5. For the name of the project, type ConnectableWebParts, and then click OK.
6. In the What local site do you want to use for debugging? drop-down list, select the local site that you want to use for debugging.
7. Select Deploy as a farm solution, and then click Finish

 B) Creating an Interface : (what is an Interface?)

   

          public interface ITextBoxString

          {

             string TextBoxString { get; set;}

          }  

C) Creating a Provider Webpart

1. In Solution Explorer, click the ConnectableWebParts project.
2. On the Project menu, click Add New Item.
3. In the Installed Templates pane, expand the SharePoint node, and then click 2010.
4. Click Web Part, type StringProvider for the name of the Web Part, and then click Add.
5. In the StringProvider.cs or StringProvider.vb code file, add the following code to indicate that the StringProvider class implements the ITextBoxString interface.

  public class StringProvider :Webpart, ITextBoxString
  
   6. Add the following code to create a text box, string and a button
 
     private TextBox myTextBox;
     private String _textBoxString = String.Empty;
     private Button myButton;

   7.  Implement the get and set method of the ItextBoxstring interface by adding the following code:
  

 
  [Personalizable()]
public string TextBoxString
{ get
    {
        return _textBoxString;
    }
    set
    {
        _textBoxString = value;
    }
}

                                               (what is personlisation)

  8. CreateChildControls(): instantiates controls and adds new control to the webpart
   
protected override void CreateChildControls()
{
    Controls.Clear();
    myTextBox = new TextBox();
    Controls.Add(myTextBox);

    myButton = new Button();
    myButton.Text = "Change Text";
    Controls.Add(myButton);
    myButton.Click += new EventHandler(myButton_Click);
}

9. Code to handel Click event

protected override void CreateChildControls()
{
    Controls.Clear();
    myTextBox = new TextBox();
    Controls.Add(myTextBox);

    myButton = new Button();
    myButton.Text = "Change Text";
    Controls.Add(myButton);
    myButton.Click += new EventHandler(myButton_Click);
}
10. Create a method to return tothe ITextBoxString object to share to other webpart.  Apply the ConnectionProviderAttribute attribute to identify the callback method that acts as the provider in a Web Parts connection.


[ConnectionProvider("Provider for String From TextBox", "TextBoxStringProvider")]
public ITextBoxString TextBoxStringProvider()
{
    return this;
}


D) Creating a Consumer Webpart

1. In Solution Explorer, click the ConnectableWebParts project.
2. On the Project menu, click Add New Item.
3. In the Installed Templates pane, expand the SharePoint node, and then click 2010.
4. Click Web Part, type StringConsumer for the name of the interface, and then click Add.
5. In the StringConsumer.cs or StringConsumer.vb code file, add the following code to create objects for an ITextBoxString provider and a text box.

private ITextBoxString _myProvider;
private Label myLabel;

protected override void OnPreRender(EventArgs e)
{
    EnsureChildControls();
    if (_myProvider != null)
    {
        myLabel.Text = _myProvider.TextBoxString;
    }
}

protected override void CreateChildControls()
{
    Controls.Clear();
    myLabel = new Label();
    myLabel.Text = "Default text";
    Controls.Add(myLabel);
}

 [ConnectionConsumer("String Consumer", "StringConsumer")]
public void TextBoxStringConsumer(ITextBoxString Provider)
{
    _myProvider = Provider;
} 

E) Connecting the Provider and Consumer Webpart

1. In Solution Explorer, click the ConnectableWebParts project.
2. On the Project menu, click Add New Item.
3. In the Installed Templates pane, click Code.
4. Click Interface.
5. Type ITextBoxString for the name of the interface, and then click Add.
6. In the ITextBoxString.cs or ITextBoxString.vb code file, mark or verify that the ITextBoxString class is public

                                                                                                                                          
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