Entity Framework Plus EF Core GetTagWithValues and GetTagWithCallSiteValues

EF Core provides query tags to help correlate LINQ queries in your code with the generated SQL captured in logs.

EF Core provides two methods for adding query tags:

• TagWith: Adds a string tag to a query.
• TagWithCallSite: Adds the file name and line number where the LINQ query is defined in the source code.

These methods make it easy to add tags, but EF Core does not provide a simple way to retrieve their values from an IQueryable.

Our library provides two utility methods:

• GetTagWithValues: Returns all string values added with TagWith.
• GetTagWithCallSiteValues: Returns all file paths and line numbers added with TagWithCallSite as a list of TagWithCallSiteInfo.

Both methods preserve the order in which the tags were added to the query.

GetTagWithValues Example

To retrieve all values added with TagWith, call GetTagWithValues on your IQueryable query.

// @nuget: Z.EntityFramework.Plus.EFCore
using Z.EntityFramework.Plus;

using (var context = new EntityContext())
{
    var query = context.EntitySimples
        .TagWith("Tag #1")
        .TagWith("Tag #2");

    List<string> tags = query.GetTagWithValues();
}

The tags variable contains "Tag #1" followed by "Tag #2", preserving the order in which they were added to the query.

GetTagWithCallSiteValues Example

To retrieve all file paths and line numbers added with TagWithCallSite, call GetTagWithCallSiteValues on your IQueryable query.

// @nuget: Z.EntityFramework.Plus.EFCore
using Z.EntityFramework.Plus;

using (var context = new EntityContext())
{
    var query = context.EntitySimples
        .TagWithCallSite("FilePath #1")
        .TagWithCallSite(filePath: "FilePath #2", lineNumber: 2)
        .TagWithCallSite(lineNumber: 3);

    List<TagWithCallSiteInfo> callSites =
        query.GetTagWithCallSiteValues();
}

The callSites variable contains one item for every TagWithCallSite call, preserving the order in which they were added to the query.

Every returned item is a TagWithCallSiteInfo with the following definition:

public class TagWithCallSiteInfo
{
    public string FilePath { get; set; }
    public int LineNumber { get; set; }
}

The FilePath and LineNumber properties contain the values associated with each TagWithCallSite call.

Summary

EF Core query tags help you identify LINQ queries in the generated SQL and application logs.

You can use:

• GetTagWithValues to retrieve all string values added with TagWith.
• GetTagWithCallSiteValues to retrieve all file paths and line numbers added with TagWithCallSite.

Both methods preserve the order in which the tags were added. They are useful when your code needs to inspect query tags and apply custom logic before the query is executed.