Several times we need to develop web applications which require to import or fetch Gmail Contacts or address book.

In this example i'm explaining how to fetch or import Gmail contacts in Asp.net web applications using C# and VB.NET.

For getting started we need to download Google Data API and install on the system to get the desired dlls. Create a new website and visual studio and put these 3 dlls in BIN folder of application from the location google data API has been installed on ur system.

1. Google.GData.Client

2. Google.GData.Contacts

3. Google.GData.Extensions

Now add references to these dlls in ur application by right clicking on solution explorer and select add reference. Now add two text box and one list box on your aspx page and design it to look better. Add one button to the page for importing the Gmail contacts or address book HTML markup of my page look like this

<form id="form1" runat="server">
    <div>
   
        <b>Email Address : </b>
        <br />
        <asp:TextBox ID="txtEmail" runat="server">
        </asp:TextBox>
        <br />
        <br />
        <b>Password : </b>
        <br />
        <asp:TextBox ID="txtPassword" runat="server"
                     TabIndex="1" TextMode="Password">
        </asp:TextBox>
        <br />
        <br />
        <asp:Button ID="btnContacts" runat="server" 
                    onclick="btnContacts_Click"
                    TabIndex="2" Text="Import Contacts"
                    Width="125px" />
        <br />
        <br />
        <br />
        <b>Contacts:<br />
        </b>
        <asp:ListBox ID="lstContacts" runat="server"
                     Height="176px"
                     Width="229px">
        </asp:ListBox>
        <br />
        <br />
   
    </div>
    </form>

Go to code behind of aspx page and add directives mentioned below
1.using Google.Contacts;

2.using Google.GData.Client;

3.using Google.GData.Contacts;

4.using Google.GData.Extensions;

Now in design view of page double click on button to generate Click event and write below mentioned code in click event of button to fetch or import gmail contacts in list box C# Code Behind

protected void btnContacts_Click(object sender, EventArgs e)
   {
        //Provide Login Information
        RequestSettings rsLoginInfo = new RequestSettings("", txtEmail.Text, txtPassword.Text);
        rsLoginInfo.AutoPaging = true;

        // Fetch contacts and dislay them in ListBox
        ContactsRequest cRequest = new ContactsRequest(rsLoginInfo);
       Feed <contact> feedContacts = cRequest.GetContacts();
        foreach (Contact gmailAddresses in feedContacts.Entries)
        {
            Console.WriteLine("\t" + gmailAddresses.Title);
         lstContacts.Items.Add(gmailAddresses.Title);
           foreach (EMail emailId in gmailAddresses.Emails)
          {
               Console.WriteLine("\t" + emailId.Address);
                lstContacts.Items.Add(" " + emailId.Address);
            }
        }

    }

Now this should show contacts in list box Hope this helps.

Thanks.