How to Retrieve Contact from Google mail by asp.net - asp.net

Question

I have been using this code because there is an error:
Execution of authentication request returned unexpected result: 404
DataSet ds = new DataSet();
ds.Tables.Add("GmailContact");
ds.Tables[0].Columns.Add("EmailId");
RequestSettings rs = new RequestSettings("GetGmailContact", txtUsername.Text, txtPassword.Text);
rs.AutoPaging = true;
ContactsRequest cr = new ContactsRequest(rs);
Feed<Contact> f = cr.GetContacts();
foreach (Contact t in f.Entries)
{
foreach (EMail email in t.Emails)
{
DataRow row = ds.Tables[0].NewRow();
row["EmailId"] = email.Address.ToString();
ds.Tables[0].Rows.Add(row);
}
}
GridView1.DataSource = ds.Tables[0];
GridView1.DataBind();
lblStatus.Text = "Total Contact For" + txtUsername.Text + ":" + ds.Tables[0].Rows.Count.ToString();

Answer 1

Step
1 Go to https://console.developers.google.com/project and create project.
2 Select project, select APIs & auth from top left corner menu.
3 Select Credentials
4 Create OAuth with button Create new Client ID (Application type - Installed Aplication.
5 Fill field Product Name
6 Save
After that you got Client ID for native application with: Client ID, Client secret, Redirect URIs
Install Google.Apis.Auth from NuGet
Code
string clientId = null; // https://console.developers.google.com/project/xxx
string clientSecret = null; // https://console.developers.google.com/project/xxx
string accessCode = null; // You will get this code after GetAccessToken method
string redirectUri = null; // https://console.developers.google.com/project/xxx
string applicationName = null; // https://console.developers.google.com/project/xxx
// Scopes https://support.google.com/a/answer/162106?hl=en
string scopes = null; // put your scope like https://www.google.com/m8/feeds/
string accessType = "offline";
string tokenType = "refresh";
OAuth2Parameters parameters = new OAuth2Parameters
{
ClientId = clientId,
ClientSecret = clientSecret,
RedirectUri = redirectUri,
Scope = scopes,
AccessType = accessType,
TokenType = tokenType
};
if (accessCode == null)
{
string url = OAuthUtil.CreateOAuth2AuthorizationUrl(parameters);
// Start webbrowser
Process.Start(url);
// Load code from web via popup, etc.
parameters.AccessCode = accessCodeFromWeb;
}
// Check accessToken and refreshToken
// After first acceess with GetAccessToken you will get that information
if (accessToken == null || refreshToken == null)
{
OAuthUtil.GetAccessToken(parameters);
// Save yours accessToken and refreshToken for next connection
accessToken = parameters.AccessToken;
refreshToken = parameters.RefreshToken;
}
else
{
// Restore your token from config file, etc.
parameters.AccessToken = accessToken;
parameters.RefreshToken = refreshToken;
}
RequestSettings rs = new RequestSettings(applicationName, parameters);
return new ContactsRequest(rs);