Hello.
I made a component that changes the value of Input depending on the button placed at the bottom.
This basically works fine, but when I save the file and restart it, the Input value is initialized.
If you press the button again after startup, it will work properly, but it is inconvenient.
Is there a solution?
Thank you.
using Grasshopper.GUI;
using Grasshopper.GUI.Canvas;
using Grasshopper.Kernel;
using Grasshopper.Kernel.Attributes;
using System;
using System.Drawing;
using System.Globalization;
using System.Windows.Forms;
namespace ExtendGUI
{
public class ExtendGuiComponent : GH_Component
{
public int Num;
public ExtendGuiComponent() : base("ExtendGUI", "ExGUI", "test", "User", "tests") { }
public override void CreateAttributes()
{
m_attributes = new AttributesCustom(this);
}
protected override void RegisterInputParams(GH_InputParamManager pManager)
{
var name = Num == 0 ? "*" : " / ";
pManager.AddNumberParameter("0", "0", "0", GH_ParamAccess.item, 0);
pManager.AddNumberParameter(name, name, "", GH_ParamAccess.item, 0);
}
protected override void RegisterOutputParams(GH_OutputParamManager pManager)
{
pManager.AddNumberParameter("Num", "N", "Number.", GH_ParamAccess.item);
}
protected override void BeforeSolveInstance()
{
var input = 0.0;
var name = "x";
if (!Params.Input[0].VolatileData.IsEmpty)
{
foreach (var item in Params.Input[0].VolatileData.AllData(false))
item.CastTo(out input);
name = input.ToString(CultureInfo.InvariantCulture);
}
Params.Input[0].Name = name;
Params.Input[0].NickName = name;
}
protected override void SolveInstance(IGH_DataAccess DA)
{
var num0 = 0.0;
if (!DA.GetData(0, ref num0)) return;
if (Params.Input.Count < 2) return;
switch (Num)
{
case 0:
{
var num1 = 0.0;
if (!DA.GetData(1, ref num1)) return;
DA.SetData(0, num0 * num1);
break;
}
case 1:
{
var num1 = 0.0;
if (!DA.GetData(1, ref num1)) return;
DA.SetData(0, num0 / num1);
break;
}
default:
DA.SetData(0, 0);
break;
}
}
public override bool Write(GH_IO.Serialization.GH_IWriter writer)
{
writer.SetInt32("Num", Num);
return base.Write(writer);
}
public override bool Read(GH_IO.Serialization.GH_IReader reader)
{
Num = reader.GetInt32("Num");
return base.Read(reader);
}
protected override Bitmap Icon => null;
public override Guid ComponentGuid => new Guid("90194116-a86f-4ef8-84e2-e480b3000c5b");
}
public class AttributesCustom : GH_ComponentAttributes
{
private Rectangle _buttonBounds0;
private Rectangle _buttonBounds1;
private GH_Capsule _button0;
private GH_Capsule _button1;
public AttributesCustom(IGH_Component owner) : base(owner) { }
protected override void Layout()
{
base.Layout();
var rec0 = GH_Convert.ToRectangle(Bounds);
rec0.Height += 44;
var rec1 = rec0;
rec1.Y = rec0.Bottom - 44;
rec1.Height = 22;
rec1.Inflate(-2, -2);
var rec2 = rec0;
rec2.Y = rec0.Bottom - 22;
rec2.Height = 22;
rec2.Inflate(-2, -2);
Bounds = rec0;
_buttonBounds0 = rec1;
_buttonBounds1 = rec2;
}
protected override void Render(GH_Canvas canvas, Graphics graphics, GH_CanvasChannel channel)
{
var extendGui = (ExtendGuiComponent)Owner;
switch (channel)
{
case GH_CanvasChannel.Objects:
RenderComponentCapsule(canvas, graphics, true, false, false, true, true, true);
_button0 = GH_Capsule.CreateTextCapsule(_buttonBounds0, _buttonBounds0, extendGui.Num == 0 ? GH_Palette.Black : GH_Palette.White, "Multiplied", 5, 0);
_button0.Render(graphics, this.Selected, Owner.Locked, Owner.Hidden);
_button0.Dispose();
_button1 = GH_Capsule.CreateTextCapsule(_buttonBounds1, _buttonBounds1, extendGui.Num == 1 ? GH_Palette.Black : GH_Palette.White, "Divided", 5, 0);
_button1.Render(graphics, this.Selected, Owner.Locked, Owner.Hidden);
_button1.Dispose();
break;
default:
base.Render(canvas, graphics, channel);
break;
}
}
public override GH_ObjectResponse RespondToMouseDown(GH_Canvas sender, GH_CanvasMouseEvent e)
{
if (e.Button != MouseButtons.Left) return base.RespondToMouseDown(sender, e);
var extendGui = (ExtendGuiComponent)Owner;
var button = ((RectangleF)_buttonBounds0).Contains(e.CanvasLocation) ? 0 :
((RectangleF)_buttonBounds1).Contains(e.CanvasLocation) ? 1 : -1;
if (button == -1) return base.RespondToMouseDown(sender, e);
if (extendGui.Num == button)
return GH_ObjectResponse.Handled;
var name = button == 0 ? "*" : " / ";
extendGui.Params.Input[1].Name = name;
extendGui.Params.Input[1].NickName = name;
extendGui.RecordUndoEvent("button");
extendGui.Num = button;
extendGui.ExpireSolution(true);
return GH_ObjectResponse.Handled;
}
}
}
ExtendGUI.zip (30.3 KB)
Thank you for your reply.
I’m very sorry, but this problem was embarrassingly due to my rudimentary mistake.
I solved it by changing the definition of the initial input of this component as in the attached file.
Thanks to your post, I am grateful to know the meaning of the Read and Write methods.
ExtendGUIComponent.cs (10.8 KB)
Thank you!
It looks like you had to register the initial inputs 
Let me ask you another question.
I added a new feature to the Component I made yesterday.
Like the Gif image, we are increasing the number of values to import.
At first glance it looks like it’s working, but when I save the file and restart it, the number of imports is incorrect.
The same thing happens when I copy the Component.
Do you know what is causing this problem?
Try implementing IGH_VariableParameterComponent in your class. It does some extra bookkeeping for a variable amount of inputs and outputs during file saving.
