1.
string sql="select * from table1 where id="+Textbox1.Text+" and name='"+Textbox2.Text+"'";
string sql=string.Format("select * from table1 where id={0} and name='{1}'",Textbox1.Text,Textbox2.Text);
2.
int i;
for(i=0;i<3;i++)
for(int i=0;i<3;i++)
3.
ClientScript.RegisterStartupScript(GetType(), "a", "alert('d');", true);
ScriptManager.RegisterStartupScript(this,GetType(), "a", "alert('d');", true);
4.
String.Compare
String.Equals
==
thx~