Linq组合查询与分页组合查询结合

1、组合查询

 <div>姓名:<asp:TextBox ID="T1" runat="server"></asp:TextBox></div>

        <div>

            性别:<asp:DropDownList ID="DropDownList1" runat="server">

                <asp:ListItem Text="男和女" Value="Null"></asp:ListItem>

                <asp:ListItem Text="男" Value="True"></asp:ListItem>

                <asp:ListItem Text="女" Value="False"></asp:ListItem>

            </asp:DropDownList>

        </div>

        <div>

            成绩:<asp:DropDownList ID="DropDownList2" runat="server">

                <asp:ListItem Text="不限" Value="Null"></asp:ListItem>

                <asp:ListItem Text="大于" Value=">"></asp:ListItem>

                <asp:ListItem Text="小于" Value="<"></asp:ListItem>

            </asp:DropDownList><asp:TextBox ID="T2" runat="server"></asp:TextBox>

        </div>

        <asp:Button ID="Button2" runat="server" Text="查询" />

 void Button2_Click(object sender, EventArgs e)

    {

        using (StudentsDataClassesDataContext con = new StudentsDataClassesDataContext())

        {

            List<Stu> s = con.Stu.ToList();

            if (T1.Text.Trim().Length > )

            { s = s.Where(r => r.Name.Contains(T1.Text.Trim())).ToList(); }

            if (DropDownList1.SelectedValue != "Null")

            {  s = s.Where(r => r.Sex == Convert.ToBoolean(DropDownList1.SelectedValue)).ToList();}

            if (DropDownList2.SelectedValue != "Null")

            {

                if (DropDownList2.SelectedValue == ">")

                { s = s.Where(r => r.Score > Convert.ToInt32((T2.Text.Trim()))).ToList(); }

                else

                { s = s.Where(r => r.Score < Convert.ToInt32((T2.Text.Trim()))).ToList(); }

            }

            Repeater1.DataSource = s;

            Repeater1.DataBind();

        }

    }

2、分页+组合查询

<div>姓名:<asp:TextBox ID="T1" runat="server"></asp:TextBox></div>

        <div>

            性别:<asp:DropDownList ID="DropDownList1" runat="server">

                <asp:ListItem Text="男和女" Value="Null"></asp:ListItem>

                <asp:ListItem Text="男" Value="True"></asp:ListItem>

                <asp:ListItem Text="女" Value="False"></asp:ListItem>

            </asp:DropDownList>

        </div>

        <div>

            成绩:<asp:DropDownList ID="DropDownList2" runat="server">

                <asp:ListItem Text="不限" Value="Null"></asp:ListItem>

                <asp:ListItem Text="大于" Value=">"></asp:ListItem>

                <asp:ListItem Text="小于" Value="<"></asp:ListItem>

            </asp:DropDownList><asp:TextBox ID="T2" runat="server"></asp:TextBox>

        </div>

        <asp:Button ID="Button2" runat="server" Text="查询" /><br />

        当前页数:<asp:Label ID="L2" runat="server" Text=""></asp:Label>

        总页数:<asp:Label ID="L3" runat="server" Text=""></asp:Label><br />

        <asp:Button ID="Button3" runat="server" Text="上一页" /><asp:Button ID="Button4" runat="server" Text="下一页" />

int Pcount = ;

    protected void Page_Load(object sender, EventArgs e)

    {

        if (!IsPostBack)

        {//绑定数据,跳过0条,取2条

            using (StudentsDataClassesDataContext con = new StudentsDataClassesDataContext())

            {

                Repeater1.DataSource = SS(con).Take(Pcount);

                Repeater1.DataBind();

                L3.Text = MaxP().ToString();

            }

            //Repeater1.DataSource = con.Stu.ToList();

            //Repeater1.DataBind();

        }

        Button1.Click += Button1_Click;

        Button2.Click += Button2_Click;

        Button3.Click += Button3_Click;

        Button4.Click += Button4_Click;

    }

    void Button4_Click(object sender, EventArgs e)

    {

        using (StudentsDataClassesDataContext con = new StudentsDataClassesDataContext())

        {

            int a = Convert.ToInt32(L2.Text) + ;

            if (a > Convert.ToInt32(MaxP()))

            { return; }

            Repeater1.DataSource = SS(con).Skip((a - ) * Pcount).Take(Pcount);

            Repeater1.DataBind();

            L2.Text = a.ToString();

        }

    }

    void Button3_Click(object sender, EventArgs e)

    {

        using (StudentsDataClassesDataContext con = new StudentsDataClassesDataContext())

        {

            int a = Convert.ToInt32(L2.Text) - ;

            if (a < )

            { return; }

            Repeater1.DataSource = SS(con).Skip((a - ) * Pcount).Take(Pcount);

            Repeater1.DataBind();

            L2.Text = a.ToString();

        }

    }

    void Button2_Click(object sender, EventArgs e)

    {

        using (StudentsDataClassesDataContext con = new StudentsDataClassesDataContext())

        {

            Repeater1.DataSource = SS(con).Take(Pcount);

            Repeater1.DataBind();

            L2.Text = "";

            L3.Text = MaxP().ToString();

        }

    }

//把组合查询封装成一个方法

    public List<Stu> SS(StudentsDataClassesDataContext con)

    {

        List<Stu> s = con.Stu.ToList();

        if (T1.Text.Trim().Length > )

        { s = s.Where(r => r.Name.Contains(T1.Text.Trim())).ToList(); }

        if (DropDownList1.SelectedValue != "Null")

        {

            s = s.Where(r => r.Sex == Convert.ToBoolean(DropDownList1.SelectedValue)).ToList();

        }

        if (DropDownList2.SelectedValue != "Null")

        {

            if (DropDownList2.SelectedValue == ">")

            { s = s.Where(r => r.Score > Convert.ToInt32((T2.Text.Trim()))).ToList(); }

            else

            { s = s.Where(r => r.Score < Convert.ToInt32((T2.Text.Trim()))).ToList(); }

        }

        return s;

    }

    ////获取最大页数

    public int MaxP()

    {

        using (StudentsDataClassesDataContext con = new StudentsDataClassesDataContext())

        {

            return Convert.ToInt32(Math.Ceiling(Convert.ToDecimal(SS(con).Count) / Pcount));

        }

    }