Sample: File Operations using Dataverse SDK for .NET

Artikkeli
12/05/2024

This .NET 6.0 sample demonstrates how to perform operations with file columns using the Dataverse SDK for .NET.

This sample uses the Microsoft.PowerPlatform.Dataverse.Client.ServiceClient.

Prerequisites

Microsoft Visual Studio 2022
Access to Dataverse with system administrator or system customizer privileges.

How to run the sample

Clone or download the PowerApps-Samples repository.
Open the PowerApps-Samples\dataverse\orgsvc\C#-NETCore\FileOperations\FileOperations.sln file using Visual Studio 2022.
Edit the appsettings.json file. Set the connection string Url and Username parameters as appropriate for your test environment.

The environment Url can be found in the Power Platform admin center. It has the form https://<environment-name>.crm.dynamics.com.
Build the solution, and then run the desired project.

When the sample runs, you will be prompted in the default browser to select an environment user account and enter a password. To avoid having to do this every time you run a sample, insert a password parameter into the connection string in the appsettings.json file. For example:

{
"ConnectionStrings": {
    "default": "AuthType=OAuth;Url=https://myorg.crm.dynamics.com;Username=someone@myorg.onmicrosoft.com;Password=mypassword;RedirectUri=http://localhost;AppId=51f81489-12ee-4a9e-aaae-a2591f45987d;LoginPrompt=Auto"
  }
}

Read the following important information about using a connection string in application code.

Important

Microsoft recommends that you use the most secure authentication flow available. The authentication flow described in this article requires a very high degree of trust in the application, and carries risks that are not present in other flows. You should only use this flow when other more secure flows, such as managed identities, aren't viable.

Tip

You can set a user environment variable named DATAVERSE_APPSETTINGS to the file path of the appsettings.json file stored anywhere on your computer. The samples will use that appsettings file if the environment variable exists and is not null. Be sure to log out and back in again after you define the variable for it to take affect. To set an environment variable, go to Settings > System > About, select Advanced system settings, and then choose Environment variables.

Sample Output

The output of the sample should look something like this:

Creating file column named 'sample_FileColumn' on the account table ...
Created file column named 'sample_FileColumn' in the account table.
Created account record with accountid:5fb4f993-7c55-ed11-bba3-000d3a9933c9
Uploading file Files\25mb.pdf ...
Uploaded file Files\25mb.pdf
Downloading file from accounts(5fb4f993-7c55-ed11-bba3-000d3a9933c9)/sample_filecolumn ...
Downloaded the file to E:\GitHub\PowerApps-Samples\dataverse\webapi\C#-NETx\FileOperations\FileOperationsWithActions\bin\Debug\net6.0//downloaded-25mb.pdf.
Deleted the file using FileId.
Deleted the account record.
Deleting the file column named 'sample_filecolumn' on the account table ...
Deleted the file column named 'sample_filecolumn' in the account table.

Demonstrates

The code for this sample is in the Program.cs file.

The project uses a Utility class to perform operations involving creating or retrieving schema data. This class is in the Utility.cs file.

This project performs these operations:

Create a file column

The Utility.CreateFileColumn function creates a file column named sample_FileColumn in the account table with a MaxSizeInKb value of 10MB.

Update a file column

The Utility.UpdateFileColumnMaxSizeInKB function updates the MaxSizeInKb value of the sample_FileColumn file column to 100MB.

Tip: If you want to create some error scenarios because the file column size is too small, comment out this line.

Retrieve the file column MaxSizeInKb value

The Utility.GetFileColumnMaxSizeInKb retrieves the MaxSizeInKb value of the sample_FileColumn file column and stores it in a variable named fileColumnMaxSizeInKb.

Create an account record

Before a file can be uploaded to the file column, a record must exist.

Upload a file

To upload a PDF file named 25MB.pdf to the sample_FileColumn file column on the account record, this sample uses an UploadFile static method that accepts all the parameters needed to make the following requests:

Initialize the upload with the InitializeFileBlocksUploadRequest Class
Process the response with the InitializeFileBlocksUploadResponse Class to get the FileContinuationToken that will be used in all the following requests.
The UploadFile method accepts a parameter named fileColumnMaxSizeInKb and uses that value to test the size of the file. If the file is larger than the configured limit of the file column, it will throw an error.
Split the file up into 4MB block and send each block using the UploadBlockRequest Class. Each instance must include a base64 encoded string to uniquely identify the block. This request doesn't have any response value to process.
After all the blocks are sent, use the CommitFileBlocksUploadRequest Class with an array of the base64 encoded string values to finalize the operation.
Process the response with the CommitFileBlocksUploadResponse Class to get the FileId value that will be used to delete the file.

Download the file

To download the PDF file named 25MB.pdf that was just uploaded to the sample_FileColumn file column on the account record, this sample uses an DownloadFile static method that accepts all the parameters needed to make the following requests:

If the file was succesfully uploaded, initialize the download with the InitializeFileBlocksDownloadRequest Class
Process the response with the InitializeFileBlocksDownloadResponse Class to get the FileContinuationToken that will be used in all the following requests.
Instantiate a List<byte> variable to capture the portions of the file as it is downloaded.
Download the file in 4MB blocks with multiple requests using the DownloadBlockRequest Class.
Process each response with the DownloadBlockResponse Class to get the partial byte[] from the Data property. Add that portion to the List<byte>.
After all the blocks are recieved, return the List<byte> as an array.
The file is saved to the current directory. You can try opening the file to confirm it was uploaded and downloaded correctly.

Delete the file

If the file was succesfully uploaded, use the DeleteFileRequest class to delete the file using the FileId value returned by the CommitFileBlocksUploadResponse. This request doesn't have any response value to process.

Clean up

To leave the system in the state before the sample ran, it does the following:

Delete the account record
Delete the file column

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