NuGet package Dax.Formatter

Dax.Formatter is a .NET client library that formats DAX expressions by calling the DAX Formatter service. It supports both single and batch requests and exposes an asynchronous API. The package is published by SQLBI under the MIT license.

• Package: Dax.Formatter on NuGet
• Source: github.com/sql-bi/DaxFormatter

The library does not format DAX itself. It sends the expression to https://api.daxformatter.com and returns the formatted result, so an internet connection is required.

Installation

Add the package to your project with the .NET CLI:

dotnet add package Dax.Formatter --version 1.2.2

Or with the Package Manager console in Visual Studio:

NuGet\Install-Package Dax.Formatter -Version 1.2.2

Usage

Quick start

Create a DaxFormatterClient and call FormatAsync with the DAX expression to format. The simplest overload takes the expression as a string and uses the default formatting options:

using Dax.Formatter;

var client = new DaxFormatterClient();
var response = await client.FormatAsync("evaluate 'Table' order by 'Table'[Column]");

Console.WriteLine(response.Formatted);

Reuse a single DaxFormatterClient instance across requests to minimize latency.

Single request

Use DaxFormatterSingleRequest when you want to set formatting options or provide model metadata while formatting one expression:

using Dax.Formatter;
using Dax.Formatter.Models;

var client = new DaxFormatterClient();
var request = new DaxFormatterSingleRequest
{
    Dax = "evaluate 'Table' order by 'Table'[Column]",
    DatabaseName = "MyDatabaseName",
    ServerName = "MyServerName",
    ListSeparator = ',',
    DecimalSeparator = '.',
    MaxLineLength = DaxFormatterLineStyle.LongLine,
    SkipSpaceAfterFunctionName = DaxFormatterSpacingStyle.BestPractice,
    ServerMode = Dax.Formatter.AnalysisServices.ServerMode.Tabular,
    ServerType = Dax.Formatter.AnalysisServices.ServerType.AnalysisServices,
    ServerEdition = Dax.Formatter.AnalysisServices.ServerEdition.Enterprise,
    ServerLocation = Dax.Formatter.AnalysisServices.ServerLocation.OnPremise,
};

var response = await client.FormatAsync(request);
Console.WriteLine(response.Formatted);

Multiple request (batch)

To format several expressions, send them in a single API call with DaxFormatterMultipleRequest. This is the recommended way to format many expressions, because it avoids one round trip per expression. Add the expressions to the Dax list; the response is a list aligned to the request order:

using Dax.Formatter;
using Dax.Formatter.Models;

var client = new DaxFormatterClient();
var request = new DaxFormatterMultipleRequest
{
    DatabaseName = "MyDatabaseName",
    ServerName = "MyServerName",
    ListSeparator = ',',
    DecimalSeparator = '.',
    MaxLineLength = DaxFormatterLineStyle.LongLine,
    SkipSpaceAfterFunctionName = DaxFormatterSpacingStyle.BestPractice,
    ServerMode = Dax.Formatter.AnalysisServices.ServerMode.Tabular,
    ServerType = Dax.Formatter.AnalysisServices.ServerType.AnalysisServices,
    ServerEdition = Dax.Formatter.AnalysisServices.ServerEdition.Enterprise,
    ServerLocation = Dax.Formatter.AnalysisServices.ServerLocation.OnPremise,
};

request.Dax.Add("evaluate 'Table' order by 'Table'[Column]");
request.Dax.Add("X=CALCULATE([Amt],USERELATIONSHIP(Sales[DueDateKey],'Date'[DateKey]))");

var responses = await client.FormatAsync(request);

foreach (var response in responses)
{
    Console.WriteLine(response.Formatted);
}

Reading errors

Formatting also validates the expression. When the DAX has a syntax error, Formatted is not returned and the Errors list describes the problem with line and column information:

var response = await client.FormatAsync("evaluate(");

if (response.Errors is { Count: > 0 })
{
    foreach (var error in response.Errors)
    {
        Console.WriteLine($"({error.Line}, {error.Column}): {error.Message}");
    }
}
else
{
    Console.WriteLine(response.Formatted);
}

The DAX Formatter services does not validate the full DAX syntax: it is possible that the expression is syntactically correct but semantically invalid.

Request parameters

DaxFormatterSingleRequest and DaxFormatterMultipleRequest share the same set of parameters (inherited from DaxFormatterRequest); the only difference is how the expression is supplied. All parameters except the DAX expression are optional: omit one to keep its default value.

The server and database parameters are telemetry context for the service and do not affect the formatted result. ServerName and DatabaseName are hashed by the library, so the actual names are never transmitted.

Formatting style values

MaxLineLength — DaxFormatterLineStyle:

SkipSpaceAfterFunctionName — DaxFormatterSpacingStyle:

Server metadata values

These enums live in the Dax.Formatter.AnalysisServices namespace and are all optional.

ServerMode: Multidimensional, SharePoint, Tabular, Default.

ServerLocation: OnPremise, Azure.

ServerType: AnalysisServices, PowerBIDesktop, PowerBIReportServer, PowerPivot, SSDT, AzureAnalysisServices, PowerBIService, Offline

ServerEdition: Standard, Standard64, Enterprise, Enterprise64, Developer, Developer64, Evaluation, Evaluation64, LocalCube, LocalCube64, BusinessIntelligence, BusinessIntelligence64, EnterpriseCore, EnterpriseCore64.

Response

FormatAsync returns a DaxFormatterResponse (or a list of them for a batch request):

Each DaxFormatterError exposes:

Key API

• DaxFormatterClient — the main client used to invoke formatting requests.
• DaxFormatterSingleRequest — describes a single-expression request.
• DaxFormatterMultipleRequest — describes a batch request with optional model metadata and formatting options.
• DaxFormatterResponse / DaxFormatterError — the formatted result and any validation errors.

Related

• MCP Server (HTTP) and MCP Server (stdio) — access the same service from AI assistants.
• GitHub repository — source code, issues, and contributions.