"The following Data Tables are missing their row structure and will not be editable."

Development Programming & Scripting C++
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1

Hi! I made a simple c++ struct, and I wanted to make a Data Table out of EGridShape, when I first create data table, I can add edit rows, everything works, but when I close the editor and turn it back on, it’s says that :

"The following Data Tables are missing their row structure and will not be editable.

* NewDataTable (Row Structure: /Script/Tactica.GridShapeData)

Do you want to open these data tables?"

And it can’t be open anymore, what am i doing wrong?

#pragma once

#include "CoreMinimal.h"
#include "Engine/DataTable.h"
#include "GridStructs.generated.h"

UENUM()
enum class EGridShape
{
	None UMETA(DisplayName = "None"),
	Square UMETA(DisplayName = "Square"),
	Triangle UMETA(DisplayName = "Triangle"),
	Hexagon UMETA(DisplayName = "Hexagon"),
};

USTRUCT(BlueprintType)
struct FGridShapeData : public FTableRowBase
{
	GENERATED_USTRUCT_BODY()

	UPROPERTY(EditAnywhere, BlueprintReadWrite, Category = GridShape)
	FName ID;
 
	UPROPERTY(EditAnywhere, BlueprintReadWrite, Category = GridShape)
	FVector MeshSize;

	UPROPERTY(EditAnywhere, BlueprintReadWrite, Category = GridShape)
	UStaticMesh* Mesh;

	UPROPERTY(EditAnywhere, BlueprintReadWrite, Category = GridShape)
	UStaticMesh* FlatMesh;

	UPROPERTY(EditAnywhere, BlueprintReadWrite, Category = GridShape)
	UMaterialInstance* MeshMaterial;

	UPROPERTY(EditAnywhere, BlueprintReadWrite, Category = GridShape)
	UMaterialInstance* FlatBorderMaterial;

	UPROPERTY(EditAnywhere, BlueprintReadWrite, Category = GridShape)
	UMaterialInstance* FlatFilledMaterial;
};
2

I’m having the exact same issue.
I created a struct in c++ to import some data table using it as row data, but when I close the editor and open it again, I can’t even find that structure in the list of row data for a new data table until I reimport everything.
But even after reimporting everything, all the places where I use that struct loose the references and I have to manually edit all the BP that were acceding it. Anyone has an idea on how to fix it? Are we doing something wrong?

3

Hi,

May you be great.

So I just made a simple adjustment in your code and it worked just fine.

  1. Add the macro YOUPROJECT_API after declare your struct.
  2. Use GENERATED_BODY.
#pragma once

#include "CoreMinimal.h"
#include "Engine/DataTable.h"
#include "GridStructs.generated.h"

UENUM()
enum class EGridShape
{
	None UMETA(DisplayName = "None"),
	Square UMETA(DisplayName = "Square"),
	Triangle UMETA(DisplayName = "Triangle"),
	Hexagon UMETA(DisplayName = "Hexagon"),
};

// 1. DEV55_API 
USTRUCT(BlueprintType)
struct DEV55_API FGridShapeData : public FTableRowBase
{
	// 2. GENERATED_BODY
	GENERATED_BODY()

	UPROPERTY(EditAnywhere, BlueprintReadWrite, Category = GridShape)
	FName ID;
 
	UPROPERTY(EditAnywhere, BlueprintReadWrite, Category = GridShape)
	FVector MeshSize;

	UPROPERTY(EditAnywhere, BlueprintReadWrite, Category = GridShape)
	UStaticMesh* Mesh;

	UPROPERTY(EditAnywhere, BlueprintReadWrite, Category = GridShape)
	UStaticMesh* FlatMesh;

	UPROPERTY(EditAnywhere, BlueprintReadWrite, Category = GridShape)
	UMaterialInstance* MeshMaterial;

	UPROPERTY(EditAnywhere, BlueprintReadWrite, Category = GridShape)
	UMaterialInstance* FlatBorderMaterial;

	UPROPERTY(EditAnywhere, BlueprintReadWrite, Category = GridShape)
	UMaterialInstance* FlatFilledMaterial;
};

@Tarkin1230, I’d like to suggest you instead of use raw pointers in your data table, try to use TSoftObjectPtr<Type>.

@Lordynn , try the solution above, it may work for as well.

4

@SpecZynk Unfortunately, this didn’t work for me. Any other ideas? I didn’t rename or move the struct, but I did try renaming it after I couldn’t resolve the issue. The issue still persists after renaming the struct and creating a new data table asset. Every time I relaunch the editor, the data table loses the reference to the struct. It’s also worth noting that the editor still sees the struct as I can create a new data table and point it to the same struct. I’ve also tried wiping the cache folders and rebuilding.

UPDATE: I forgot to wipe the plugin cache folders where the struct actually resides, but that didn’t work, either.

UPDATE 2: It appears to finally have sorted itself out? I purged cache folders again, and did a clean/rebuild of the projects. So far so good. I also applied the change mentioned here to hopefully avoid having this happen, again. Basically, enabling the “Force Compilation on Startup” option. Others seemed to have success with it, so hoping for the same.

UPDATE 3: Things seemed fine after a couple of restarts, but it has started happening, again. I’m on 5.5.3

UPDATE 4: Finally fixed it! Thanks to this post, I realized that I needed to change the LoadingPhase of my plugin from “Default” to “PreDefault” (or earlier).

1 Like
5

The loading phase can be one cause. For others, it might also be a problem related to Live Coding:

Structs (and sometimes also Classes), when compiled through Live Coding, can run into issues. It should work, but Live Coding is still a bit buggy from time to time and Patches don’t get properly reapplied when opening the Project again, most of the time a build through the IDE instead of Live Coding will fix it, but sometimes the Intermediate folder needs to be purged.

Funny enough, the Loading Phase is sometimes even an issue with Unreal Plugins. As far as I remember, the Audio Capture Plugin would sometimes throw Errors about missing structs through UE 5.1-5.3 with every restart. If I remember correctly, it was an issue with the loading phase. So yeah, it’s sometimes really annoying.

Hopefully, it helps someone at some point in the future :smiley:

1 Like