Restrict TextField input

Hi,
I want to make a `FileNameTextField` or `FileNameManipulator` that restrict input so that user can only enter a file name friendly string.

My first try was to simply make a manipulator and stopping KeyDown event propagation if the character was invalid. That simply didn't affect TextField value.

The second attempt looked like this:

Code (CSharp):

1.  
2.     public class FileNameField : TextValueField<string>
3.     {
4.         public FileNameField(): base(null, -1, new FileNameInput())
5.         {
6.         }
7.  
8.         public override void ApplyInputDeviceDelta(Vector3 delta, DeltaSpeed speed, string startValue)
9.         {
10.         }
11.  
12.         protected override string StringToValue(string str) => str;
13.  
14.         protected override string ValueToString(string value) => value;
15.  
16.         class FileNameInput : TextValueInput
17.         {
18.             protected override string allowedCharacters => "test";
19.  
20.             public override void ApplyInputDeviceDelta(Vector3 delta, DeltaSpeed speed, string startValue)
21.             {
22.                
23.             }
24.  
25.             protected override string ValueToString(string value) => value;
26.         }
27.     }

It did filter the characters but started to throw `NotSupportedException: Specified method is not supported` every time I typed character. Also, I think that doing this by manipulator would be a much cleaner approach.

So, what is the proper way to do this?

 

This is it:

Spoiler: Log

NotSupportedException: Specified method is not supported.
UnityEngine.UIElements.TextInputBaseField`1+TextInputBase[TValueType].StringToValue (System.String str) (at /Users/builduser/buildslave/unity/build/Modules/UIElements/Controls/TextInputFieldBase.cs:242)
UnityEditor.UIElements.TextValueField`1+TextValueInput[TValueType].StringToValue (System.String str) (at /Users/builduser/buildslave/unity/build/Editor/Mono/UIElements/Controls/TextValueField.cs:133)
UnityEngine.UIElements.TextInputBaseField`1+TextInputBase[TValueType].UpdateValueFromText () (at /Users/builduser/buildslave/unity/build/Modules/UIElements/Controls/TextInputFieldBase.cs:247)
UnityEditor.UIElements.TextValueField`1+TextValueInput[TValueType].ExecuteDefaultActionAtTarget (UnityEngine.UIElements.EventBase evt) (at /Users/builduser/buildslave/unity/build/Editor/Mono/UIElements/Controls/TextValueField.cs:173)
UnityEngine.UIElements.CallbackEventHandler.HandleEvent (UnityEngine.UIElements.EventBase evt) (at /Users/builduser/buildslave/unity/build/Modules/UIElements/Events/EventHandler.cs:106)
UnityEngine.UIElements.EventDispatchUtilities.PropagateEvent (UnityEngine.UIElements.EventBase evt) (at /Users/builduser/buildslave/unity/build/Modules/UIElements/Events/IEventDispatchingStrategy.cs:95)
UnityEngine.UIElements.KeyboardEventDispatchingStrategy.DispatchEvent (UnityEngine.UIElements.EventBase evt, UnityEngine.UIElements.IPanel panel) (at /Users/builduser/buildslave/unity/build/Modules/UIElements/Events/KeyboardEventDispatchingStrategy.cs:30)
UnityEngine.UIElements.EventDispatcher.ProcessEvent (UnityEngine.UIElements.EventBase evt, UnityEngine.UIElements.IPanel panel) (at /Users/builduser/buildslave/unity/build/Modules/UIElements/EventDispatcher.cs:277)
UnityEngine.UIElements.EventDispatcher.Dispatch (UnityEngine.UIElements.EventBase evt, UnityEngine.UIElements.IPanel panel, UnityEngine.UIElements.DispatchMode dispatchMode) (at /Users/builduser/buildslave/unity/build/Modules/UIElements/EventDispatcher.cs:159)
UnityEngine.UIElements.BaseVisualElementPanel.SendEvent (UnityEngine.UIElements.EventBase e, UnityEngine.UIElements.DispatchMode dispatchMode) (at /Users/builduser/buildslave/unity/build/Modules/UIElements/Panel.cs:245)
UnityEngine.UIElements.UIElementsUtility.DoDispatch (UnityEngine.UIElements.BaseVisualElementPanel panel) (at /Users/builduser/buildslave/unity/build/Modules/UIElements/UIElementsUtility.bindings.cs:359)
UnityEngine.UIElements.UIElementsUtility.ProcessEvent (System.Int32 instanceID, System.IntPtr nativeEventPtr) (at /Users/builduser/buildslave/unity/build/Modules/UIElements/UIElementsUtility.bindings.cs:154)
UnityEngine.GUIUtility.ProcessEvent (System.Int32 instanceID, System.IntPtr nativeEventPtr) (at /Users/builduser/buildslave/unity/build/Modules/IMGUI/GUIUtility.cs:179)

 

Thanks Jonathan,
I was hoping for someone to hint a solution that doesn't depends on

TextValueField

but for now this works.
For anyone interested this is the working snippet:

Code (CSharp):

1.     public class FileNameField : TextValueField<string>
2.     {
3.         public FileNameField() : base(null, -1, new FileNameInput()) { }
4.  
5.         public override void ApplyInputDeviceDelta(Vector3 delta, DeltaSpeed speed, string startValue) { }
6.  
7.         protected override string StringToValue(string str) => str;
8.  
9.         protected override string ValueToString(string value) => value;
10.  
11.         class FileNameInput : TextValueInput
12.         {
13.             private readonly string _allowedChars;
14.  
15.             protected override string allowedCharacters => _allowedChars;
16.  
17.             public FileNameInput()
18.             {
19.                 _allowedChars = new string(Enumerable.Range(char.MinValue, char.MaxValue)
20.                     .Select(c => (char)c)
21.                     .Where(c => !char.IsControl(c))
22.                     .Except(Path.GetInvalidFileNameChars())
23.                     .ToArray());
24.             }
25.  
26.             public override void ApplyInputDeviceDelta(Vector3 delta, DeltaSpeed speed, string startValue) { }
27.  
28.             protected override string ValueToString(string value) => value;
29.  
30.             protected override string StringToValue(string str) => str;
31.         }
32.     }