private void Form1_Deactivate(object sender, EventArgs e)
ExpandedBlockStart.gifContractedBlock.gif        
{
            
if (this.WindowState == FormWindowState.Minimized)
                
this.Visible = false;
        }

还有种方法更加直接,重载WndProc:

const int WM_SYSCOMMAND = 0x112;
const int SC_CLOSE = 0xF060;
const int SC_MINIMIZE = 0xF020;
const int SC_MAXIMIZE = 0xF030;
protected override void WndProc(ref Message m)
ExpandedBlockStart.gifContractedBlock.gif
{
    
if (m.Msg == WM_SYSCOMMAND)
ExpandedSubBlockStart.gifContractedSubBlock.gif    
{
        
if (m.WParam.ToInt32() == SC_MINIMIZE)
ExpandedSubBlockStart.gifContractedSubBlock.gif        
{
            
this.Visible = false;
            
return;
        }

    }

    
base.WndProc(ref m);
}