4.24 UK2Node FName pin as drop down

[Qygon]

I am trying to achieve something similar to this


This question was asked before here, but since it was never answered and I have been trying for a couple of days now with no success, I thought I'd ask again and also share what I have found out.

So after trying to build my own node so that it can have a drop down, without success of course, I literally copied the source code of the UK2Node_GetDataTableRow to my UK2Node_GetDataTableRow_2 and thats the result



At this point I'm not even sure if it is even possible, the node works exactly the same but without showing a drop down for the Row Name

If anyone as any suggestion, I'd really appreciate it.

I posted the same thing in the Answer Hub here

[BrUnO XaVIeR]

The K2 node uses custom widgets.
That drop-down is done using a Text combo box widget:

https://docs.unrealengine.com/en-US/...Box/index.html

[Qygon]

Could you give me some more information on how to get started with using widgets for K2 nodes, I read about it once on the wiki, but since that's gone now I'm a little lost.
And since there is no reference of any widget on the UK2Node_GetDataTableRow it must be declared somewhere else.

But thanks anyways, maybe I'll figure it out myself.

[BrUnO XaVIeR]

First thing to do is find out what kind of node Pin is used for "RowName", there must be custom types declared somewhere in the module's source code.

[Qygon]

Do you mean this part?

// Row Name pin
UEdGraphPin* RowNamePin = CreatePin(EGPD_Input, UEdGraphSchema_K2::PC_Name, UK2Node_GetDataTableRow_2Helper::RowNamePinName);

That means it's a UEdGraphSchema_K2::PC_Name meaning it's a FName.

[Qygon]

Because of this comment in the UK2Node_GetDataTableRow source

// When the DataTable pin gets a new value assigned, we need to update the Slate UI so that SGraphNodeCallParameterCollectionFunction will update the ParameterName drop down

I started digging to find references of the UK2Node_GetDataTableRow node, because it wasn't working for my copy and the comment suggest the drop down is generated somewhere else.... and I found this in BlueprintGraphPanelPinFactory.cpp

else if (Outer->IsA(UK2Node_GetDataTableRow::StaticClass()))
        {
            const UK2Node_GetDataTableRow* GetDataTableRowNode = CastChecked<UK2Node_GetDataTableRow>(Outer);
            DataTablePin = GetDataTableRowNode->GetDataTablePin();
        }

        if (DataTablePin)
        {
            if (DataTablePin->DefaultObject != nullptr && DataTablePin->LinkedTo.Num() == 0)
            {
                if (auto DataTable = Cast<UDataTable>(DataTablePin->DefaultObject))
                {
                    return SNew(SGraphPinDataTableRowName, InPin, DataTable);
                }
                if (DataTablePin->DefaultObject->IsA(UCurveTable::StaticClass()))
                {
                    UCurveTable* CurveTable = (UCurveTable*)DataTablePin->DefaultObject;
                    if (CurveTable)
                    {
                        TArray<TSharedPtr<FName>> RowNames;
                        /** Extract all the row names from the RowMap */
                        for (TMap<FName, FRealCurve*>::TConstIterator Iterator(CurveTable->GetRowMap()); Iterator; ++Iterator)
                        {
                            /** Create a simple array of the row names */
                            TSharedPtr<FName> RowNameItem = MakeShareable(new FName(Iterator.Key()));
                            RowNames.Add(RowNameItem);
                        }
                        return SNew(SGraphPinNameList, InPin, RowNames);
                    }
                }
            }
        }

It looks very promising, I don't have a lot of time rn, so I'll look into it later, but I'll post my findings here

[andrea.b]

Because of this comment in the UK2Node_GetDataTableRow source

// When the DataTable pin gets a new value assigned, we need to update the Slate UI so that SGraphNodeCallParameterCollectionFunction will update the ParameterName drop down

I started digging to find references of the UK2Node_GetDataTableRow node, because it wasn't working for my copy and the comment suggest the drop down is generated somewhere else.... and I found this in BlueprintGraphPanelPinFactory.cpp

else if (Outer->IsA(UK2Node_GetDataTableRow::StaticClass()))
{
const UK2Node_GetDataTableRow* GetDataTableRowNode = CastChecked<UK2Node_GetDataTableRow>(Outer);
DataTablePin = GetDataTableRowNode->GetDataTablePin();
}

if (DataTablePin)
{
if (DataTablePin->DefaultObject != nullptr && DataTablePin->LinkedTo.Num() == 0)
{
if (auto DataTable = Cast<UDataTable>(DataTablePin->DefaultObject))
{
return SNew(SGraphPinDataTableRowName, InPin, DataTable);
}
if (DataTablePin->DefaultObject->IsA(UCurveTable::StaticClass()))
{
UCurveTable* CurveTable = (UCurveTable*)DataTablePin->DefaultObject;
if (CurveTable)
{
TArray<TSharedPtr<FName>> RowNames;
/** Extract all the row names from the RowMap */
for (TMap<FName, FRealCurve*>::TConstIterator Iterator(CurveTable->GetRowMap()); Iterator; ++Iterator)
{
/** Create a simple array of the row names */
TSharedPtr<FName> RowNameItem = MakeShareable(new FName(Iterator.Key()));
RowNames.Add(RowNameItem);
}
return SNew(SGraphPinNameList, InPin, RowNames);
}
}
}
}

It looks very promising, I don't have a lot of time rn, so I'll look into it later, but I'll post my findings here

Hi Qygon, I was trying to do something similar.
Probably you're already figured it out, but I discovered that it's possible to create custom FGraphPinPanelFactory and register them like this:

TSharedPtr<FBlueprintGraphPanelPinFactory> BlueprintGraphPanelPinFactory = MakeShareable(new FBlueprintGraphPanelPinFactory());
FEdGraphUtilities::RegisterVisualPinFactory(BlueprintGraphPanelPinFactory);

This code can put inside a module Startup function (for example an editor plugin). This seems what it need to be done in order to have custom pins for custom UK2Nodes.

[Qygon]

Hi, I did figure it out, I was just busy but I will try to post my solution here in the near future.

Basically you create your own PinFactory then register that factory just like the Post above shows

TSharedPtr<FBlueprintGraphPanelPinFactory> BlueprintGraphPanelPinFactory = MakeShareable(new FBlueprintGraphPanelPinFactory());
FEdGraphUtilities::RegisterVisualPinFactory(BlueprintGraphPanelPinFactory);

Then you have to set up how your Pin is represented and do something similar to this, just in your Factory and probably not with a DataTable

if (DataTablePin)
{
    if (DataTablePin->DefaultObject != nullptr && DataTablePin->LinkedTo.Num() == 0)
   {
      if (auto DataTable = Cast<UDataTable>(DataTablePin->DefaultObject))
      {
         return SNew(SGraphPinDataTableRowName, InPin, DataTable);
      }
      if (DataTablePin->DefaultObject->IsA(UCurveTable::StaticClass()))
      {
         UCurveTable* CurveTable = (UCurveTable*)DataTablePin->DefaultObject;
         if (CurveTable)
         {
            TArray<TSharedPtr<FName>> RowNames;
            /** Extract all the row names from the RowMap */
            for (TMap<FName, FRealCurve*>::TConstIterator Iterator(CurveTable->GetRowMap()); Iterator; ++Iterator)
            {
               /** Create a simple array of the row names */
               TSharedPtr<FName> RowNameItem = MakeShareable(new FName(Iterator.Key()));
               RowNames.Add(RowNameItem);
            }
            return SNew(SGraphPinNameList, InPin, RowNames);
         }
      }
   }
}

Like I said I will post some code from my project for further explanation in the near future.