How to integrate Outlook Mail (Office 365) using C#

Learn how to quickly and efficiently connect Outlook Mail (Office 365) with C# for smooth data access.

Read and write Microsoft Outlook Mail (Office 365) data effortlessly. Send, manage, and sync messages, attachments, and folders — almost no coding required. You can do it all using the high-performance Outlook Mail (Office 365) ODBC Driver for C# (often referred to as the Outlook Mail (Office 365) Connector). We'll walk you through the entire setup.

Ready to dive in? Download the product to jump right in, or follow the step-by-step guide below to see how it works.

Create data source using Outlook Mail (Office 365) ODBC Driver

Step-by-step instructions

To get data from Outlook Mail (Office 365) using C#, we first need to create an ODBC data source. We will later read this data in C#. Perform these steps:

1. Download and install ODBC PowerPack (if you haven't already).

2. Search for odbc and open the ODBC Data Sources (64-bit):

   

3. Create a User data source (User DSN) based on the ZappySys API Driver driver:

   ZappySys API Driver

   
   • Create and use a User DSN if the client application runs under a User Account. This is the ideal option at design time (e.g., when developing in Visual Studio). Use it for both types of applications (64-bit and 32-bit).
   • Create and use a System DSN if the client application runs under a System Account (e.g., as a Windows Service). This is usually the required option in a production environment. If your Windows Service is a 32-bit application, you must use the 32-bit ODBC Data Source Administrator to configure this

4. When the Configuration window appears give your data source a name if you haven't done that already, then select "Outlook Mail (Office 365)" from the list of Popular Connectors. If "Outlook Mail (Office 365)" is not present in the list, then click "Search Online" and download it. Then set the path to the location where you downloaded it. Finally, click Continue >> to proceed with configuring the DSN:

   OutlookMailOffice365DSN

   Outlook Mail (Office 365)

   

5. Now it's time to configure the Connection Manager. Select Authentication Type, e.g. Token Authentication. Then select API Base URL (in most cases, the default one is the right one). More info is available in the Authentication section.

   User Credentials

   Outlook Mail (Office 365) authentication

   Use delegated access (User Credentials) whenever you want to let a signed-in user work with their own resources or resources they can access. Whether it's an admin setting up policies for their entire organization or a user deleting an email in their inbox, all scenarios involving user actions should use delegated access. [API reference]

   Follow these simple steps below to create Microsoft Entra ID application with delegated access:

   WARNING: If you are planning to automate processes, we recommend that you use a Application Credentials authentication method. In case, you still need to use User Credentials, then make sure you use a system/generic account (e.g. automation@my-company.com). When you use a personal account which is tied to a specific employee profile and that employee leaves the company, the token may become invalid and any automated processes using that token will start to fail.

   1. Navigate to the Azure Portal and log in using your credentials.
   2. Access Microsoft Entra ID.
   3. Register a new application by going to App registrations and clicking on New registration button:
      INFO: Find more information on how to register an application in Graph API reference.
   4. When configuration window opens, configure these fields:
      • Supported account type
        • Use Accounts in this organizational directory only, if you need access to data in your organization only.
      • Redirect URI:
        • Set the type to Public client/native (mobile & desktop).
        • Use https://zappysys.com/oauth as the URL.
      
   5. After registering the app, copy the Application (client) ID for later:
   6. Then copy OAuth authorization endpoint (v2) & OAuth token endpoint (v2) URLs to use later in the configuration:
   7. Now go to SSIS package or ODBC data source and use the copied values in User Credentials authentication configuration:
      • In the Authorization URL field paste the OAuth authorization endpoint (v2) URL value you copied in the previous step.
      • In the Token URL field paste the OAuth token endpoint (v2) URL value you copied in the previous step.
      • In the Client ID field paste the Application (client) ID value you copied in the previous step.
      • In the Scope field use the default value or select individual scopes, e.g.:
        • email
        • offline_access
        • openid
        • profile
        • Mail.Read
        • Mail.Read.Shared
        • Mail.ReadBasic
        • Mail.ReadBasic.Shared
        • Mail.ReadWrite
        • Mail.ReadWrite.Shared
        • Mail.Send
        • Mail.Send.Shared
        • User.Read
        • User.ReadBasic.All
        • Group.Read.All
   8. Press Generate Token button to generate Access and Refresh Tokens.
   9. Optional step. Choose Default User Id from the drop down menu (if someone shared a mailbox with you).
   10. Click Test Connection to confirm the connection is working.
   11. Done! Now you are ready to use the API Connector!

   API Connection Manager configuration

   Just perform these simple steps to finish authentication configuration:

   1. Set Authentication Type to User Credentials [OAuth]
   2. Optional step. Modify API Base URL if needed (in most cases default will work).
   3. Fill in all the required parameters and set optional parameters if needed.
   4. Press Generate Token button to generate the tokens.
   5. Finally, hit OK button:

   OutlookMailOffice365DSN

   Outlook Mail (Office 365)

   User Credentials [OAuth]

   https://graph.microsoft.com/v1.0

   Required Parameters
   Authorization URL	Fill-in the parameter...
   Token URL	Fill-in the parameter...
   Client ID	Fill-in the parameter...
   Scope	Fill-in the parameter...
   Return URL	Fill-in the parameter...
   Optional Parameters
   Client Secret
   Refresh Token File Path
   Login Prompt Option
   Default User Id (Select after clicking **Generate Token**)	me
   RetryMode	RetryWhenStatusCodeMatch
   RetryStatusCodeList	429|503
   RetryCountMax	5
   RetryMultiplyWaitTime	True

   

   Application Credentials

   Outlook Mail (Office 365) authentication

   Application-only access is broader and more powerful than delegated access (User Credentials), so you should only use app-only access where needed. Use it when: 1. The application needs to run in an automated way, without user input (for example, a daily script that checks emails from certain contacts and sends automated responses). 2. The application needs to access resources belonging to multiple different users (for example, a backup or data loss prevention app might need to retrieve messages from many different chat channels, each with different participants). 3. You find yourself tempted to store credentials locally and allow the app to sign in 'as' the user or admin. [API reference]

   Follow these simple steps below to create Microsoft Entra ID application with application access permissions.

   1. Navigate to the Azure Portal and log in using your credentials.
   2. Access Microsoft Entra ID.
   3. Register a new application by going to App registrations and clicking on New registration button:
      INFO: Find more information on how to register an application in Graph API reference.
   4. When configuration window opens, configure these fields:
      • Supported account type
        • e.g. select Accounts in this organizational directory only if you need access to data in your organization only.
      • Redirect URI:
        • Set the type to Public client/native (mobile & desktop).
        • Leave the URL field empty.
      
   5. After registering the app, copy the Application (client) ID for later:
   6. Then copy OAuth authorization endpoint (v2) & OAuth token endpoint (v2) URLs:
   7. Continue and create Client secret:
   8. Then copy the Client secret for later steps:
   9. Continue by adding permissions for the app by going to the API permissions section, and clicking on Add a permission:
   10. Select Microsoft Graph:
   11. Then choose Application permissions option:
   12. Continue by adding these Mail (Outlook) permissions:
   13. Finish by clicking Add permissions button:
   14. Now it's time to Grant admin consent for your application:
   15. Confirm all the permissions are granted:
   16. Now go to SSIS package or ODBC data source and use the copied values in Application Credentials authentication configuration:
       • In the Token URL field paste the OAuth token endpoint (v2) URL value you copied in the previous step.
       • In the Client ID field paste the Application (client) ID value you copied in the previous step.
       • In the Client Secret field paste the Client secret value you copied in the previous step.
       • Choose Default User Id from the drop down menu.
   17. Click Test Connection to confirm the connection is working.
   18. That's it! Now you can use the connector.

   API Connection Manager configuration

   Just perform these simple steps to finish authentication configuration:

   1. Set Authentication Type to Application Credentials [OAuth]
   2. Optional step. Modify API Base URL if needed (in most cases default will work).
   3. Fill in all the required parameters and set optional parameters if needed.
   4. Finally, hit OK button:

   OutlookMailOffice365DSN

   Outlook Mail (Office 365)

   Application Credentials [OAuth]

   https://graph.microsoft.com/v1.0

   Required Parameters
   Token URL	Fill-in the parameter...
   Client ID	Fill-in the parameter...
   Client Secret	Fill-in the parameter...
   Scope	Fill-in the parameter...
   Default User Id	Fill-in the parameter...
   Optional Parameters
   RetryMode	RetryWhenStatusCodeMatch
   RetryStatusCodeList	429|503
   RetryCountMax	5
   RetryMultiplyWaitTime	True

   

6. Once the data source connection has been configured, it's time to configure the SQL query. Select the Preview tab and then click Query Builder button to configure the SQL query:

   

   ZappySys API Driver - Outlook Mail (Office 365)

   Read and write Microsoft Outlook Mail (Office 365) data effortlessly. Send, manage, and sync messages, attachments, and folders — almost no coding required.

   OutlookMailOffice365DSN

   

7. Start by selecting the Table or Endpoint you are interested in and then configure the parameters. This will generate a query that we will use in C# to retrieve data from Outlook Mail (Office 365). Hit OK button to use this query in the next step.

   SELECT * FROM MyMessages

   
   Some parameters configured in this window will be passed to the Outlook Mail (Office 365) API, e.g. filtering parameters. It means that filtering will be done on the server side (instead of the client side), enabling you to get only the meaningful data much faster.

8. Now hit Preview Data button to preview the data using the generated SQL query. If you are satisfied with the result, use this query in C#:

   

   ZappySys API Driver - Outlook Mail (Office 365)

   Read and write Microsoft Outlook Mail (Office 365) data effortlessly. Send, manage, and sync messages, attachments, and folders — almost no coding required.

   OutlookMailOffice365DSN

   SELECT * FROM MyMessages

   
   You can also access data quickly from the tables dropdown by selecting <Select table>.
   A WHERE clause, LIMIT keyword will be performed on the client side, meaning that the whole result set will be retrieved from the Outlook Mail (Office 365) API first, and only then the filtering will be applied to the data. If possible, it is recommended to use parameters in Query Builder to filter the data on the server side (in Outlook Mail (Office 365) servers).

9. Click OK to finish creating the data source.

Video Tutorial

Read data in C#

Using ODBC DSN

1. Use this code snippet to read the data using OutlookMailOffice365DSN data source:

   "OutlookMailOffice365DSN" ;

   

2. Press F5 to run the code and read the data:
   

3. Here is the code in text format:

   using System;
   using System.Data.Odbc;
   
   namespace ConsoleApp {
       class Program {
           static void Main() {
               var dsn = "OutlookMailOffice365DSN";
               using (var conn = new OdbcConnection(String.Format("DSN={0}", dsn)))
               {
                   conn.Open();
                   var cmd = new OdbcCommand("SELECT * FROM Products", conn);
                   
                   //Increase the timeout duration from the default 30 seconds, which may be insufficient in certain scenarios
                   cmd.CommandTimeout=600; // 600-Seconds
                   
                   var rdr = cmd.ExecuteReader();
                   while (rdr.Read())
                   {
                       for (int i = 0; i < rdr.FieldCount; i++)
                       {
                               Console.Write("{0}\t", rdr[i]);
                       }
                       Console.WriteLine();
                   }
               }
               Console.ReadKey();
           }
       }
   }
   

Using a full ODBC connection string

If you want to avoid being dependent on a DSN and creating multiple DSNs for each platform (x86, x64), then you can use a fully qualified connection string. Simply go to your DSN and copy the Connection String:

1. Open ODBC data source configuration and click Copy settings:
   

   ZappySys API Driver - Configuration [Version: 2.0.1.10418]

   ZappySys API Driver - Outlook Mail (Office 365)

   Read and write Microsoft Outlook Mail (Office 365) data effortlessly. Send, manage, and sync messages, attachments, and folders — almost no coding required.

   OutlookMailOffice365DSN

   
2. The window opens, telling us the connection string was successfully copied to the clipboard:

3. Then in your C# code, pass the connection string as an argument when calling the OdbcConnection object's constructor, for example:

   var connectionString = @"DRIVER={ZappySys API Driver};ServiceUrl=https://graph.microsoft.com/v1.0;Provider=Custom;OAuthVersion=OAuth2;GrantType=Default;Scope=[$Scope$];ScopeSeparator={space};";
   
   using (var conn = new OdbcConnection(connectionString))
   {
       // your code goes here
   }

Handling limitations of using a full connection string

Despite using a full ODBC connection string may be very convenient it comes with a limitation: it's length is limited to 1024 symbols (or sometimes more). It usually happens when API provider generates a very long Refresh Token when OAuth is at play. If you are using such a long ODBC connection string, you may get this error:

"Connection string exceeds maximum allowed length of 1024"

But there is a solution to this by storing the full connection string in a file. Follow the steps below to achieve this:

1. Open your ODBC data source.
2. Click Copy settings button to copy a full connection string (see the previous section on how to accomplish that).
3. Then create a new file, let's say, in C:\temp\odbc-connection-string.txt.
4. Continue by pasting the copied connection string into a newly created file and save it.
5. Finally, the last step! Just construct a shorter ODBC connection string using this format:

   DRIVER={ZappySys API Driver};SettingsFile=C:\temp\odbc-connection-string.txt

6. Our troubles are over! Now you should be able to use this connection string in C# with no problems.

Optional: Centralized data access via ZappySys Data Gateway

In some situations, you may need to provide Outlook Mail (Office 365) data access to multiple users or services. Configuring the data source on a Data Gateway creates a single, centralized connection point for this purpose.

This configuration provides two primary advantages:

• Centralized data access
  The data source is configured once on the gateway, eliminating the need to set it up individually on each user's machine or application. This significantly simplifies the management process.
• Centralized access control
  Since all connections route through the gateway, access can be governed or revoked from a single location for all users.

To achieve this, you must first create a data source in the Data Gateway (server-side) and then create an ODBC data source in C# (client-side) to connect to it.

Let's not wait and get going!

Create Outlook Mail (Office 365) data source in the gateway

In this section we will create a data source for Outlook Mail (Office 365) in the Data Gateway. Let's follow these steps to accomplish that:

1. Search for gateway in the Windows Start Menu and open ZappySys Data Gateway Configuration:

   

2. Go to the Users tab and follow these steps to add a Data Gateway user:

   • Click the Add button
   • In the Login field enter a username, e.g., john
   • Then enter a Password
   • Check the Is Administrator checkbox
   • Click OK to save
   

3. Now we are ready to add a data source:

   • Click the Add button
   • Give the Data source a name (have it handy for later)
   • Then select Native - ZappySys API Driver
   • Finally, click OK
   OutlookMailOffice365DSN

   ZappySys API Driver

   

4. When the ZappySys API Driver configuration window opens, go back to ODBC Data Source Administrator where you already have the Outlook Mail (Office 365) ODBC data source created and configured, and follow these steps on how to Import data source configuration into the Gateway:

   • Open ODBC data source configuration and click Copy settings:
     

     ZappySys API Driver - Configuration [Version: 2.0.1.10418]

     ZappySys API Driver - Outlook Mail (Office 365)

     Read and write Microsoft Outlook Mail (Office 365) data effortlessly. Send, manage, and sync messages, attachments, and folders — almost no coding required.

     OutlookMailOffice365DSN

     
   • The window opens, telling us the connection string was successfully copied to the clipboard:

   • Then go to Data Gateway configuration and in data source configuration window click Load settings:

     OutlookMailOffice365DSN

     

     ZappySys API Driver - Configuration [Version: 2.0.1.10418]

     ZappySys API Driver - Outlook Mail (Office 365)

     Read and write Microsoft Outlook Mail (Office 365) data effortlessly. Send, manage, and sync messages, attachments, and folders — almost no coding required.

     OutlookMailOffice365DSN

     
   • Once a window opens, just paste the settings by pressing CTRL+V or by clicking right mouse button and then Paste option.

5. Once done, go to the Network Settings tab and Add a firewall rule for inbound traffic:

   
   • This will initially allow all inbound traffic.
   • Click Edit IP filters to restrict access to specific IP addresses or ranges.

6. Crucial Step: After creating or modifying the data source, you must:

   • Click the Save button to persist your changes.
   • Hit Yes when prompted to restart the Data Gateway service.

   This ensures all changes are properly applied:

   
   Skipping this step may cause the new settings to fail, preventing you from connecting to the data source.

Create ODBC data source to connect to the gateway

In this part we will create an ODBC data source to connect to the ZappySys Data Gateway from C#. To achieve that, let's perform these steps:

1. Search for odbc and open the ODBC Data Sources (64-bit):

   

2. Create a User data source (User DSN) based on the ODBC Driver 17 for SQL Server driver:

   ODBC Driver 17 for SQL Server

   
   If you don't see the ODBC Driver 17 for SQL Server driver in the list, choose a similar version.

3. Then set a Name for the data source (e.g. Gateway) and the address of the Data Gateway:

   ZappySysGatewayDSN

   localhost,5000

   
   Make sure you separate the hostname and port with a comma, e.g. localhost,5000.

4. Proceed with the authentication part:

   • Select SQL Server authentication
   • In the Login ID field enter the user name you created in the Data Gateway, e.g., john
   • Set Password to the one you configured in the Data Gateway
   

5. Then set the default database property to OutlookMailOffice365DSN (the one we used in the Data Gateway):

   OutlookMailOffice365DSN

   OutlookMailOffice365DSN

   
   Make sure to type the data source name manually or copy/paste it directly into the field. Using the dropdown might fail because the Trust server certificate option is not enabled yet (next step).

6. Continue by checking the Trust server certificate option:

   

7. Once you do that, test the connection:

   

8. If the connection is successful, everything is good:

   

9. Done!

We are ready to move to the final step. Let's do it!

Access data in C# via the gateway

Finally, we are ready to read data from Outlook Mail (Office 365) in C# via the Data Gateway. Follow these final steps:

1. Go back to C#.

2. Use this code snippet to read the data using ZappySysGatewayDSN data source:

   "ZappySysGatewayDSN" ;

   

3. Read the data the same way we discussed at the beginning of this article.

4. That's it!

Now you can connect to Outlook Mail (Office 365) data in C# via the Data Gateway.

Supported Outlook Mail (Office 365) Connector actions

Got a specific use case in mind? We've mapped out exactly how to perform a variety of essential Outlook Mail (Office 365) operations directly in C#, so you don't have to figure out the setup from scratch. Check out the step-by-step guides below:

• Delete Message by Id (Single)
• Delete Messages - Using Search Condition (Bulk Delete)
• Download Message Attachment (Single File)
• Download Message Attachments (Multiple Files) - Using Search Condition
• Download Message by Id (Single *.EML File RFC 822 or MIME)
• Download Messages by Search Condition (Multiple *.EML Files RFC 822 or MIME)
• Get Group by Id
• Get Groups
• Get Mail Folder by Id [only works with User Credentials]
• Get Mail Folders
• Get Message Attachment
• Get Message Attachments
• Get Message by Id (Single) - Output binary data (EML RFC 822 or MIME)
• Get Messages
• Get Messages by Search Filters - Output binary data (EML RFC 822 or MIME)
• Get My Information
• Get My Mail Folders [only works with User Credentials]
• Get My Message by Id [only works with User Credentials]
• Get My Messages [only works with User Credentials]
• Get Table Columns
• Get Tables
• Get User by Id
• Get Users
• Send Mail
• Make Generic REST API Request
• Make Generic REST API Request (Bulk Write)

Conclusion

In this article we showed you how to connect to Outlook Mail (Office 365) in C# and integrate data without writing complex code — all of this was powered by Outlook Mail (Office 365) ODBC Driver.

Download ODBC PowerPack now or ping us via chat if you have any questions or are looking for a specific feature (you can also reach out to us by submitting a ticket):

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