How to update a field of datatype of File or Image

[KASCHN]

I am building a PCF for a custom page and one of the controls is an input that allows a user to upload a file attachment to a column of datatype file.

I feel like there is more than one step in updating the database with the file content because the following does not work.

          const fileString = {
            slp_file: {
              fileContent:
                "PD94bWwgdmVyc2lvbj0iMS4wIiBzdGFuZGFsb25lPSJubyI/Pg0KPHN2ZyB3aWR0aD0iMTYiIGhlaWdodD0iMTYiIHZlcnNpb249IjEuMSIgeG1sbnM9Imh0dHA6Ly93d3cudzMub3JnLzIwMDAvc3ZnIj4NCiAgICA8cmVjdCB4PSIwIiB5PSIwIiB3aWR0aD0iMTYiIGhlaWdodD0iMTYiIHN0cm9rZT0iYmxhY2siIGZpbGw9InJlZCIgc3Ryb2tlLXdpZHRoPSIwIi8+DQo8L3N2Zz4=",
              fileName: "Square_Red_16x16.svg",
              fileSize: 215,
              mimeType: "image/svg+xml",
            },
          };

const newRecord = Xrm.WebApi.updateRecord(this.resultItem.logicalName, this.id, fileString).then(
              (r) => r,
              (e) => console.log(e),
            );
          };

 I keep getting the following error.

 1: An error occurred while validating input parameters: Microsoft.OData.ODataException: An unexpected 'StartObject' node was found for property named 'slp_file' when reading from the JSON reader. A 'PrimitiveValue' node was expected. 

Is there a table like fileattachment to create the file first and then associate the link to this record to the actual field in my table?

Does anyone know what steps I should take to save the selected file to the database to a field that has datatype or "File" or "Image".

[GuidoPreite]

If the column is Image you can update the image using the base64 encoded value directly as a property, for example:

var record = {};
record.sample_image = ""; // Base 64 Image

Xrm.WebApi.online.updateRecord("sample_customtable", "", record).then(
	function success(result) {
		var updatedId = result.id;
		console.log(updatedId);
	},
	function(error) {
		console.log(error.message);
	}
);

for a File column I am not aware of an Xrm.WebApi method compatible, because the content needs to be set as binary and just updating that specific property, you can do with a Fetch o jQuery but not with Xrm.WebApi

you can use my tool Dataverse REST Builder if you need to create such queries

[KASCHN]

@GuidoPreite Thank you so much. Yes this worked for an image datatype column. The file datatype column is still a mystery to me. Obviously, the column is looking for a reference to a file. I think it is more of a lookup column. What I can't figure out is which table I would use to store the file and then reference in my file datatype column. Would it be any of these tables?

•     "fileattachment",
•     "msdyn_richtextfile",
•     "activityfileattachment",

[GuidoPreite]

File column contents are not stored inside Dataverse, so you will not find a table hosting that information.

As I wrote before there isn't (afaik) a direct Xrm.WebApi method to upload a content to a file column.

[KASCHN]

Thank you again. I am leaving this open a bit longer as I am still researching. There is now the setValue() method on a dataset record that will accept a file object. I took the "afaik" (as far as I know?) comment to mean that I can remain hopeful.