Transparent background on winforms?

Question

I wanted to make my windows form transparent so removed the borders, controls and everything leaving only the forms box, then I tried to the BackColor and TransparencyKey to

Answer 1

I had drawn a splash screen (32bpp BGRA) with "transparent" background color in VS2013 and put a pictureBox in a form for display. For me a combination of above answers worked:

public Form1()
{
    InitializeComponent();

    SetStyle(ControlStyles.SupportsTransparentBackColor, true);
    this.BackColor = this.pictureBox1.BackColor;
    this.TransparencyKey = this.pictureBox1.BackColor;
}

So make sure you use the same BackColor everywhere and set that color as the TransparencyKey.