Question

C#中winform 中MDI的子窗体始终填充满父窗体,不论父窗体大小如何变化

Answer 1

frm就是你的子窗体,在frm.Show()之后添加此句就行了
frm.Dock = DockStyle.Fill;

Answer 2

private void Form1_Load(object sender, EventArgs e)
{
this.WindowState = FormWindowState.Maximized;
}