c# example for ImGuiTextFilter

I was trying to use ImGuiTextFilter but couldn’t find a c# example of it. I looked at the ImGui demo code example and tried to replicate that on ImGui.NET but failed. Here’s the code I was using, let me know how to use this feature.

ImGuiTextFilter testing = new ImGuiTextFilter();
testing.draw()

I did find the ImGuiTextFilterPtr struct/class but not sure how to use it.

reference c++ eample

static ImGuiTextFilter filter;
filter.draw();
        const char* lines[] = { "aaa1.c", "bbb1.c", "ccc1.c", "aaa2.cpp", "bbb2.cpp", "ccc2.cpp", "abc.h", "hello, world" };
        for (int i = 0; i < IM_ARRAYSIZE(lines); i++)
            if (filter.PassFilter(lines[i]))
                ImGui::BulletText("%s", lines[i]);

[prime31]

For the sake of completeness and future visitors, here is an ImGuiTextFilter example as well:

unsafe public class CleanTest
{
    string[] _lines = { "aaa1.c", "bbb1.c", "ccc1.c", "aaa2.cpp", "bbb2.cpp", "ccc2.cpp", "abc.h", "hello, world" };
    ImGuiTextFilterPtr _filter;

    public CleanTest()
    {
        var filterPtr = ImGuiNative.ImGuiTextFilter_ImGuiTextFilter(null);
        _filter = new ImGuiTextFilterPtr(filterPtr);
    }

    public void Draw()
    {
        ImGui.Begin("Here We Go");

        _filter.Draw("This is a text filter");

        foreach(var line in _lines)
        {
            if (_filter.PassFilter(line))
                ImGui.BulletText(line);
        }

        ImGui.End();
    }

    public void Destroy()
    {
        ImGuiNative.ImGuiTextFilter_destroy(_filter.NativePtr);
    }
}

[mellinoe]

I pushed two changes to master that fix the raw PInvokes for constructor and destructor functions:

https://github.com/mellinoe/ImGui.NET/commit/8e3caa1b49bd6b8df5bb277c52c5bb9c32115813 https://github.com/mellinoe/ImGui.NET/commit/4588142ef950d3e474de5635a99f890b55095570

Ideally, there would be static functions that invoke the native constructor, with default parameters being generated as with other overloads. Right now, you can invoke the functions added in the first commit and get back a raw pointer, which needs to be deleted later with a matching thing_destroy call.

Another note: you could already create these structures on the C# side and pass a pointer to them to the native side. Where it gets tricky is:

• ImVector – The native side will likely try to reallocate the buffer at some point, and things will probably not work. If you preallocate a large enough vector, it might work. This matters for ImGuiTextFilter because it contains a vector.
• Default values – Allocating the struct in C# will zero-init everything, which means it won’t have the default values it would have in C++: for example.
• Lifetime – if you’re passing a pointer to the C# object, you need to make sure it remains valid (e.g. not on the stack if it’s long-lived).