透明TextBox - 当改变文本时OnPaint不会触发

Question

我的控件正确地以透明方式启动，但是一旦我输入文本，它就会进入常规的白色背景。如果我将鼠标移到控件上，它会再次触发OnPaint，并能够正确地绘制带有文本的控件。如何在输入文本时绘制透明背景？

默认值：

输入文字后直接：

将鼠标移动后，强制OnPaint触发：

ref class CustomTextBox : System::Windows::Forms::TextBox
{
public:

    CustomTextBox()
    {
        SetStyle(ControlStyles::SupportsTransparentBackColor, true);
        SetStyle(ControlStyles::OptimizedDoubleBuffer, true); //Tried this both ways
        SetStyle(ControlStyles::AllPaintingInWmPaint, true);
        SetStyle(ControlStyles::ResizeRedraw, true);
        SetStyle(ControlStyles::UserPaint, true);

        BackColor = Color::Transparent;
        ForeColor = Color::Red;
    }

    virtual void OnPrint(PaintEventArgs^ e) override
    {
        System::Windows::Forms::TextBox::OnPrint(e);
Debug::WriteLine("OnPrint: " + this->Text);
    }

    virtual void OnPaintBackground(PaintEventArgs^ e) override
    {
        System::Windows::Forms::TextBox::OnPaintBackground(e);
Debug::WriteLine("OnPaintBackground: " + this->Text);

    }

    virtual void OnPaint(PaintEventArgs^ e) override
    {
        //System::Windows::Forms::TextBox::OnPaint(e);

        //Paint Background
        Graphics^ g = e->Graphics;
        RectangleF^ bounds = gcnew RectangleF(0, 0, Convert::ToSingle(this->Width - 1), Convert::ToSingle(this->Height - 1));
        e->Graphics->FillRectangle(gcnew SolidBrush(this->BackColor), *bounds);

        //Paint text
        g->DrawString(this->Text,this->Font,gcnew SolidBrush(Color::Red),1,1);

Debug::WriteLine("OnPaint: " + this->Text);

    }

};

Answer 1

仅供参考 - 找到解决方案：

1）将TextChanged事件绑定到每次输入文本时将触发的方法。 2）在新方法中，标记控件：control->Invalidate()以触发重新绘制。