Question

有关ASP.NET的一段代码看不懂请高手解释下，最好是每句都解释！谢谢啊

#endregion

private void logbut_Click(object sender, System.EventArgs e)
{

string connectionString=ConfigurationSettings.AppSettings["connectstr"].ToString();
SqlConnection sampleConnection = new SqlConnection(connectionString);

sampleConnection.ConnectionString = connectionString;

sampleConnection.Open();

string cmd="select * from users where teacherid='"+name.Text.ToString()+"'and passwd='"+password.Text.ToString()+"'";
SqlCommand mycommand=new SqlCommand(cmd,sampleConnection);

SqlDataReader dr=mycommand.ExecuteReader();

if(dr.Read())
{
if(dr["role"].ToString()=="普通用户")
{
Session["uid"]=dr["teacherid"].ToString();
Session["role"]=dr["role"].ToString();
Response.Redirect("teachers.aspx");
}
else
{
Session["uid"]=dr["teacherid"].ToString();
Session["role"]=dr["role"].ToString();
Response.Redirect("users.aspx");
}

}
else
{
Response.Write("<script>alert(\"用户名或者密码错误！\")</script>");
}

sampleConnection.Close();
}

private void thbtn_Click(object sender, System.EventArgs e)
{
string searchstr=thddl.SelectedValue.ToString()+"="+thbox.Text.ToString();
Response.Redirect("teachersearch.aspx?"+searchstr);
}

private void pbtn_Click(object sender, System.EventArgs e)
{
string searchstr=pddl.SelectedValue.ToString()+"="+pbox.Text.ToString();
Response.Redirect("projectsearch.aspx?"+searchstr);
}

private void pabtn_Click(object sender, System.EventArgs e)
{
string searchstr=paddl.SelectedValue.ToString()+"="+pabox.Text.ToString();
Response.Redirect("papersearch.aspx?"+searchstr);
}
}
}

Answer 1

logbut_Click这段
从数据库的users表中查询是否存在teacherid为name.Text和passwd为password.Text的记录。
如是不存在dr.Read()为0则弹出“用户名或者密码错误！”对话框，否则
如果role为普通用户，在填写Session后转到teachers.aspx
否则在填写Session后转到users.aspx
其它几个就不用说了吧

Answer 2

这回没时间 你 如果不嫌麻烦 你 留个 邮箱 我 发给你 保证 每句都解释