How to See What EF Core Will Save with ChangeTracker.DebugView

When SaveChangesAsync does something you didn't expect, or nothing at all, you need to see what EF Core thinks has changed. ChangeTracker.DebugView.LongView prints it: every tracked entity, its state, each property's value, and what changed from what. This guide reads it for a real change.

Prerequisites

• A .NET C# project with EF Core. The examples use EF Core 10, Oracle's MySql.EntityFrameworkCore, MySQL 9.7, and a products table.

Step 1: Print It

DebugView is a property on the change tracker. EF Core's debug views page says it "provides a human-readable view of all entities being tracked". This endpoint prints it twice, before and after changing one property:

A temporary endpoint

app.MapPost("/demo/debugview/{id:int}", async (int id, InventoryDbContext db) =>
{
    var product = await db.Products.FirstAsync(p => p.Id == id);
    var before = db.ChangeTracker.DebugView.LongView;

    product.ReorderLevel += 1;
    db.ChangeTracker.DetectChanges();
    var after = db.ChangeTracker.DebugView.LongView;

    var saved = await db.SaveChangesAsync();
    return Results.Text($"BEFORE\n{before}\nAFTER\n{after}\nSAVED {saved}\n");
});

DetectChanges() makes EF Core compare the objects with their original values now. SaveChangesAsync does this by itself, so you only need it to see the state before saving.

Step 2: Read the Output

Response

BEFORE
Product {Id: 3} Unchanged
    Id: 3 PK
    ArchivedAtUtc: <null>
    CategoryId: 1 FK
    CreatedAtUtc: '04/11/2026 11:42:47 AM'
    Description: <null>
    IsArchived: 'False'
    Name: 'HDMI cable, 2 m'
    QuantityOnHand: 0
    ReorderLevel: 5
    Sku: 'CBL-HDMI-2M'
    UnitPrice: 12.25
    UpdatedAtUtc: '04/11/2026 11:42:47 AM'
    Version: 0
  Category: <null>

AFTER
Product {Id: 3} Modified
    Id: 3 PK
    ArchivedAtUtc: <null>
    CategoryId: 1 FK
    CreatedAtUtc: '04/11/2026 11:42:47 AM'
    Description: <null>
    IsArchived: 'False'
    Name: 'HDMI cable, 2 m'
    QuantityOnHand: 0
    ReorderLevel: 6 Modified Originally 5
    Sku: 'CBL-HDMI-2M'
    UnitPrice: 12.25
    UpdatedAtUtc: '04/11/2026 11:42:47 AM'
    Version: 0
  Category: <null>

SAVED 1

Line by line:

• Product {Id: 3} Unchanged is the entity, its key and its state. After the change, it says Modified.
• Id: 3 PK, CategoryId: 1 FK mark the primary and foreign keys.
• ReorderLevel: 6 Modified Originally 5 is the line you came for: the property's new value, and what it was.
• Category: <null> is the navigation. It wasn't loaded.
• SAVED 1 at the end is what SaveChangesAsync returned: one row.

The UPDATE that followed set only what's marked Modified:

API log

info: Microsoft.EntityFrameworkCore.Database.Command[20101]
      Executed DbCommand (5ms) [Parameters=[@p1='?' (DbType = Int32), @p0='?' (DbType = Int32), @p2='?' (DbType = Int32)], CommandType='Text', CommandTimeout='30']
      UPDATE `products` SET `ReorderLevel` = @p0
      WHERE `Id` = @p1 AND `Version` = @p2;
      SELECT ROW_COUNT();

Use It to Debug

What you see	What it means
The entity isn't listed	It isn't tracked, for example it came from AsNoTracking or Select, so saving won't touch it
State Unchanged after you changed it	The value is the same as before, so there's nothing to save
State Added for a row that exists	You called Add on an existing object
State Modified on every property	Someone called Update, which marks them all

For a quick look in the debugger, there's also ShortView, with one line per entity. Don't leave either in production code: they're for debugging.

Common Mistakes

Mistake	What happens	Do this instead
Reading LongView without DetectChanges	Changes you made may not be marked yet	Call DetectChanges first
Returning it from a real endpoint	It exposes your data	Use it in development only
Logging it in production	It has every value of every tracked entity	Keep it out of production logs

FAQ

Does reading DebugView change anything?

No. It only reports. DetectChanges updates the tracker's own state, which SaveChangesAsync would have done anyway.

Where do I see it without changing code?

In a debugger, expand db.ChangeTracker.DebugView and read LongView.

Conclusion

db.ChangeTracker.DebugView.LongView lists every tracked entity, its state, and each property, with Modified Originally … on what changed. Call DetectChanges() first, read it when SaveChangesAsync surprises you, and keep it out of production.

Additional Resources

• Change Tracker Debugging — LongView, ShortView and debug logging.
• Change Detection and Notifications — when EF Core compares values.

Related

• EF Core Entity States Explained: Detached, Added, Unchanged, Modified and Deleted
• How to Update a Row with EF Core and SaveChangesAsync