protected void Button1_Click(object sender, EventArgs e)
    {
        LoginName = name.Text.Trim();
        Password = pwd.Text.Trim();
        string idstring;
        uis.Login(LoginName,Password);

        DataTable sdr = uis.Login(LoginName,Password);
        if(sdr!=null)
        {
            idstring=sdr.Rows[0][0].ToString();
            Session["userid"] = idstring;
            Response.Write("<script>alert('登陆成功')</script>");
        }
        else
        {        
            Response.Write("<script>alert('用户名密码错误')</script>");
        }

我的button事件是用Datatable接受的 用户名密码  可是当用户名密码正确的时候正常  但是错误的时候 也进if了 并报错说Rows里面没有行 为什么呢？应该怎么写if条件？

public DataTable Login(string LoginName,string Password)  我的Login方法
    {
        String where = " where LoginName='" + LoginName + "'and Password='" + Password + "'";
        return user.SelectUserInfos(where);
    }


public DataTable SelectUserInfos(string where)   SelectUserInfos方法
    {
        string sql = "select * from userinfo ";
        if (!string.IsNullOrEmpty(where))
        {
            sql += where;
        }
        return db.Search(sql);
    }


public DataTable Search(string sql)   Search方法  全都是用DataTable接收的
    {
        this.ConnectDataBase();
        DataSet ds = new DataSet();
        SqlDataAdapter da = new SqlDataAdapter(sql,conn);
        da.Fill(ds);
        return ds.Tables[0];
    }

[[it] 本帖最后由 chairmancui 于 2008-3-27 14:24 编辑 [/it]]