Filter GridView based on Minimum and Maximum Date Ranges in ASP.Net

Hi @nauna,

Hi have made a small snippet for you.

Please have a look

SQL

CREATE PROCEDURE Students_GetStudents
	@StartDate DATETIME 
	,@EndDate DATETIME 
	,@FilterBy INT = 1
AS
BEGIN
	SET NOCOUNT ON;

    IF @FilterBy = 1
	BEGIN
		SELECT Id
			,Name
			,City
			,StartDate
			,EndDate
			,MAX(Marks) Marks
		FROM Table_Students
		WHERE StartDate = @StartDate
		AND EndDate = @EndDate
		GROUP BY Id
			,Name
			,City
			,StartDate
			,EndDate
	END
	ELSE
	BEGIN
			SELECT Id
			,Name
			,City
			,StartDate
			,EndDate
			,MIN(Marks) Marks
		FROM Table_Students
		WHERE StartDate = @StartDate
		AND EndDate = @EndDate
		GROUP BY Id
			,Name
			,City
			,StartDate
			,EndDate
	END
END
GO

HTML

 <div>
        <div>
            Start Date:<asp:TextBox ID="txtStartDate" runat="server"></asp:TextBox>
            <br />
            End Date:
            <asp:TextBox ID="txtEndDate" runat="server"></asp:TextBox>
            Filter By:<asp:DropDownList ID="ddlFilterValues" runat="server" AppendDataBoundItems="true">
                <asp:ListItem Text="Max" Value="1" Selected="True"></asp:ListItem>
                <asp:ListItem Text="Min" Value="2"></asp:ListItem>
            </asp:DropDownList>
            <br />
            <asp:Button ID="btnFilter" runat="server" Text="Filter" OnClick="Filter" />
        </div>
        <asp:GridView ID="gvStudents" runat="server" AutoGenerateColumns="false">
            <Columns>
                <asp:BoundField DataField="Name" HeaderText="Name" />
                <asp:BoundField DataField="City" HeaderText="City" />
                <asp:BoundField DataField="StartDate" HeaderText="Start Date" />
                <asp:BoundField DataField="EndDate" HeaderText="End Date" />
                <asp:BoundField DataField="Marks" HeaderText="Marks" />
            </Columns>
        </asp:GridView>
    </div>

C# Code

        SqlConnection con =new SqlConnection(ConfigurationManager.ConnectionStrings["ConString"].ConnectionString);
        SqlCommand cmd;
        protected void Page_Load(object sender, EventArgs e)
        {
            if (!this.IsPostBack)
            {
                cmd = new SqlCommand("SELECT Name,City,StartDate,EndDate,Marks FROM Table_Students",con);
                this.gvStudents.DataSource = this.GetData(cmd);
                this.gvStudents.DataBind();
            }
        }

        protected void Filter(object sender, EventArgs e)
        {
            if (!string.IsNullOrEmpty(this.txtStartDate.Text.Trim()) && !string.IsNullOrEmpty(this.txtEndDate.Text.Trim()))
            {
                DateTime startDate = Convert.ToDateTime(this.txtStartDate.Text.Trim());
                DateTime endDate = Convert.ToDateTime(this.txtEndDate.Text.Trim());
                cmd = new SqlCommand("Students_GetStudents",con);
                cmd.Parameters.AddWithValue("@StartDate",startDate);
                cmd.Parameters.AddWithValue("@EndDate",endDate);
                cmd.Parameters.AddWithValue("@FilterBy",this.ddlFilterValues.SelectedItem.Value);
                cmd.CommandType = CommandType.StoredProcedure;
                this.gvStudents.DataSource=this.GetData(cmd);
                this.gvStudents.DataBind();
            }
        }

        private DataTable GetData(SqlCommand cmd)
        {
            SqlDataAdapter da = new SqlDataAdapter(cmd);
            DataTable dt = new DataTable();
            da.Fill(dt);
            return dt;
        }

Namespaces

using System;
using System.Data.SqlClient;
using System.Configuration;
using System.Data;