在C#程序中, 显示一个信息为”This is test!”，标题为“Hello”的消息框，正确的语句是( )
A.MessageBox("this is a test!","Hello");
B.MessageBox .Show("this is a test!","Hello");
C.MessageBox("Hello","this is a test!");
D.MessageBox.Show ("Hello","this is a test!");
正确答案B 
在C#程序中, 显示一个信息为”This is test!”，标题为“Hello”的消息框，正确的语句是( )
A.MessageBox("this is a test!","Hello");
B.MessageBox .Show("this is a test!","Hello");
C.MessageBox("Hello","this is a test!");
D.MessageBox.Show ("Hello","this is a test!");
正确答案B 