Sử dụng Dropdownlist để lọc dữ liệu trong Gridview HeaderTemplate

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(Lọc dữ liệu từ Dropdownlist trong Gridview) – Chức năng AutoFilter trong Excel giúp người sử dụng lọc và tìm dữ liệu dễ dàng và thuận tiện. Chỉ cần kích vào mũi tên tại mỗi cột dữ liệu, một danh sách lựa chọn xuất hiện và người dùng chỉ cần chọn thì toàn bộ dữ liệu sẽ được lọc theo tiêu chí đã chọn.

Xem những Video hay dành cho thiếu nhi - Nghe trên Youtube

Quay lại danh sách dữ liệu trong Gridview, người dùng sẽ rất khó để xem dữ liệu nếu không có các điều kiện để lọc. Bài viết dưới đây sẽ hướng dẫn các bạn cách xây dựng các điều kiện lọc trong chính các HeaderTemplate của Gridview.

- B1: Download CSDL Northwind

- B2: Bổ xung thêm stored procedure trong SQL Server

USE [Northwind]

CREATE PROCEDURE [dbo].[Pro_Products_List]

@Keyword nvarchar(250),

@SupplierID int,

@CategoryID int

declare @strSQL nvarchar(1000)

declare @strWhere nvarchar(500)

declare @strOrder nvarchar (50)

set @strSQL= 'SELECT Products.ProductID, Products.ProductName, Products.SupplierID, Suppliers.CompanyName, Products.CategoryID,

Categories.CategoryName, Products.QuantityPerUnit, Products.UnitPrice, Products.UnitsInStock,

Products.UnitsOnOrder, Products.ReorderLevel, Products.Discontinued

FROM Products INNER JOIN

Suppliers ON Products.SupplierID = Suppliers.SupplierID INNER JOIN

Categories ON Products.CategoryID = Categories.CategoryID'

set @strWhere =' Where 1=1 '

if @Keyword<>''

set @strWhere= @strWhere +' And (ProductName like N''%' +@Keyword+'%'')'

if @SupplierID <>-1

set @strWhere= @strWhere + ' and (Products.SupplierID='+ convert(nvarchar,@SupplierID) + ')'

if @CategoryID <>-1

set @strWhere= @strWhere + ' and (Products.CategoryID='+ convert(nvarchar,@CategoryID) + ')'

set @strOrder =' Order by Products.ProductName'

set @strSQL=@strSQL+@strWhere+@strOrder

print @strSQL

exec sp_executesql @strSQL

- B3: Tạo Project trong Microsoft Visual Studio 2010

Trong Visual Studio tạo 1 Class có tên: Utility và nhập đoạn Code phía dưới cho Class này.

Imports System.Data.SqlClient

Imports System.Data

Namespace FilterRecordsUsingDropDownListInHeaderTemplate

Public Class SqlDataProvider

#Region "Membres Prives"

Shared _IsError As Boolean = False

Private _connectionString As String

#End Region

#Region "Constructeurs"

Public Sub New()

Try

_connectionString = ConfigurationManager.ConnectionStrings("SiteSqlServer").ConnectionString

_IsError = False

Catch ex As Exception

_IsError = True

End Try

End Sub

#End Region

#Region "Proprietes"

Public ReadOnly Property ConnectionString() As String

Get

Return _connectionString

End Get

End Property

#End Region

#Region "Functions"

Public Function FillTable(ByVal sql As String) As DataTable

Try

Dim tb As New DataTable

Dim adap As New SqlDataAdapter(sql, _connectionString)

adap.Fill(tb)

Return tb

Catch ex As Exception

Return Nothing

End Try

End Function

Public Function FillTable(ByVal ProcName As String, ByVal ParamArray Para() As ObjectPara) As DataTable

Try

Dim tb As New DataTable

Dim adap As New SqlDataAdapter(ProcName, _connectionString)

adap.SelectCommand.CommandType = CommandType.StoredProcedure

If Not Para Is Nothing Then

For Each p As ObjectPara In Para

adap.SelectCommand.Parameters.Add(New SqlParameter(p.Name, p.Value))

End If

adap.Fill(tb)

Return tb

Catch ex As Exception

Return Nothing

End Try

End Function

#End Region

End Class

Public Class ObjectPara

Dim _name As String

Dim _Value As Object

Sub New(ByVal Pname As String, ByVal PValue As Object)

_name = Pname

_Value = PValue

End Sub

Public Property Name() As String

Get

Return _name

End Get

Set(ByVal value As String)

_name = value

End Set

End Property

Public Property Value() As Object

Get

Return _Value

End Get

Set(ByVal value As Object)

_Value = value

End Set

End Property

End Class

End Namespace

Chú ý: Thuộc tính SiteSqlServer chính là chuỗi Connect với SQL Server trong file Web.Config

- B4: Mở file Default.aspx dưới dạng HTML và nhập mã HTML

<%@ Page Title="Filter Records using DropDownList in GridView HeaderTemplate in ASP.Net" Language="vb" MasterPageFile="~/Site.Master" AutoEventWireup="false" EnableEventValidation= "false" CodeBehind="Default.aspx.vb" Inherits="FilterRecordsUsingDropDownListInHeaderTemplate._Default" %>

<asp:Content ID="BodyContent" runat="server" ContentPlaceHolderID="MainContent">

<asp:ScriptManager ID="ScriptManager1" runat="server">

</asp:ScriptManager>

<h3>

Filter Records using DropDownList in GridView HeaderTemplate in ASP.Net

</h3>

<asp:UpdatePanel ID="updatePanel" runat="server" UpdateMode="Conditional">

<tr>

<td>

<h4>

<asp:Label ID="lblTotal" runat="server" Visible="false"></asp:Label>

</h4>

</td>

<asp:TextBox ID="txtSearch" CssClass="form-control" ToolTip="Enter Keyword" runat="server" width="200px"></asp:TextBox>

<asp:ImageButton ID="cmdQuickSearch" runat="server" causesvalidation="false" imageurl="~/images/icon_search.gif"></asp:ImageButton>

</td>

</tr>

<tr>

<asp:GridView ID="grvObject" runat="server" AllowPaging="true" PageSize="10" ShowHeaderWhenEmpty="true"

CssClass="GridStyle" BorderColor="#cbcbcb" BorderStyle="solid"

BorderWidth="1" AutoGenerateColumns="false" DataKeyNames="ProductID" width="100%">

<asp:BoundField ItemStyle-Width="16%" DataField="ProductName" HeaderText="ProductName" />

<asp:TemplateField HeaderText="Supplier">

Supplier

<asp:DropDownList ID="ddlSupplier" Width="180" CssClass="form-control" runat="server" AppendDataBoundItems="true" OnSelectedIndexChanged="SupplierChanged" AutoPostBack="true">

</asp:DropDownList>

</HeaderTemplate>

<asp:Label ID="lblSupplier" Text='<%# Eval("CompanyName") %>' runat="server" />

</ItemTemplate>

</asp:TemplateField>

<asp:TemplateField HeaderText="Category">

Category

<asp:DropDownList ID="ddlCategory" CssClass="form-control" runat="server" AppendDataBoundItems="true" OnSelectedIndexChanged="CategoryChanged" AutoPostBack="true">

</asp:DropDownList>

</HeaderTemplate>

<asp:Label ID="lblCategory" Text='<%# Eval("CategoryName") %>' runat="server" />

</ItemTemplate>

</asp:TemplateField>

<asp:TemplateField HeaderText="QuantityPerUnit">

<asp:Label ID="lblQuantityPerUnit" Text='<%# Eval("QuantityPerUnit") %>' runat="server" />

</ItemTemplate>

</asp:TemplateField>

<asp:TemplateField HeaderText="UnitPrice">

<asp:Label ID="lblUnitPrice" Text='<%# Eval("UnitPrice") %>' runat="server"></asp:Label>

</ItemTemplate>

</asp:TemplateField>

</Columns>

</asp:GridView>

</td>

</tr>

<tr>

<asp:label id="lblMessage" runat="server" Text="No Data"></asp:label>

</td>

</tr>

</table>

</td>

</tr>

</table>

</ContentTemplate>

</asp:UpdatePanel>

</asp:Content>

- B5: Viết Code cho file Default.aspx

C# Code

//Visit http://www.laptrinhdotnet.com for more ASP.NET Tutorials

using Microsoft.VisualBasic;

using System;

using System.Collections;

using System.Collections.Generic;

using System.Data;

using System.Web.UI;

using System.Web.UI.WebControls;

using System.Web.UI.HtmlControls;

using System.Diagnostics;

namespace FilterRecordsUsingDropDownListInHeaderTemplate

{

public partial class _Default : System.Web.UI.Page

{

#region "ComboData"

private void LoadDropDownList(DropDownList ucControl, string DataValueField, string DataTextField, string sql)

{

SqlDataProvider objSQL = new SqlDataProvider();

DataTable objBind = objSQL.FillTable(sql);

ucControl.Items.Clear();

if (objBind != null)

{

ucControl.DataTextField = DataTextField;

ucControl.DataValueField = DataValueField;

ucControl.DataSource = objBind;

ucControl.DataBind();

ucControl.Items.Insert(0, (new ListItem("---All---", "-1")));

}

#endregion

#region "Bind Data"

private void BindProducts()

{

DataTable objBind = new DataTable();

int iTotal = 0;

int SupplierID = -1;

int CategoryID = -1;

if (ViewState["Filter_Supplier"] != null)

{

SupplierID = Convert.ToInt32(ViewState["Filter_Supplier"]);

}

if (ViewState["Filter_Category"] != null)

{

CategoryID = Convert.ToInt32(ViewState["Filter_Category"]);

}

objBind = BindData(txtSearch.Text, SupplierID, CategoryID);

if (objBind != null)

{

if (objBind.Rows.Count > 0)

{

iTotal = objBind.Rows.Count;

grvObject.DataSource = objBind;

grvObject.DataBind();

trMessage.Visible = false;

lblTotal.Visible = true;

lblTotal.Text = "Total " + iTotal + " records";

}

else

{

trMessage.Visible = true;

lblTotal.Visible = false;

grvObject.DataSource = new List<string>();

grvObject.DataBind();

}

updatePanel.Update();

}

private DataTable BindData(string Keyword, int SupplierID, int CategoryID)

{

SqlDataProvider objSQL = new SqlDataProvider();

DataTable objBind = objSQL.FillTable("Pro_Products_List", new ObjectPara("@Keyword", Keyword.Trim()), new ObjectPara("@SupplierID", SupplierID), new ObjectPara("@CategoryID", CategoryID));

return objBind;

}

#endregion

#region "GridView Methods"

protected void grvObject_RowDataBound(object sender, System.Web.UI.WebControls.GridViewRowEventArgs e)

{

if (e.Row.RowType == DataControlRowType.Header)

{

string sSQL = "Select distinct Suppliers.SupplierID, Suppliers.CompanyName From Products INNER JOIN Suppliers on Products.SupplierID = Suppliers.SupplierID";

DropDownList ddlSupplier = (DropDownList)e.Row.FindControl("ddlSupplier");

if (ddlSupplier != null)

{

LoadDropDownList(ddlSupplier, "SupplierID", "CompanyName", sSQL);

if (ViewState["Filter_Supplier"] != null)

{

ddlSupplier.Items.FindByValue(ViewState["Filter_Supplier"].ToString()).Selected = true;

}

DropDownList ddlCategory = (DropDownList)e.Row.FindControl("ddlCategory");

if (ddlCategory != null)

{

sSQL = "Select distinct Categories.CategoryID, Categories.CategoryName From Products INNER JOIN Categories on Products.CategoryID = Categories.CategoryID";

LoadDropDownList(ddlCategory, "CategoryID", "CategoryName", sSQL);

if (ViewState["Filter_Category"] != null)

{

ddlCategory.Items.FindByValue(ViewState["Filter_Category"].ToString()).Selected = true;

}

protected void grvObject_PageIndexChanging(object sender, System.Web.UI.WebControls.GridViewPageEventArgs e)

{

grvObject.PageIndex = e.NewPageIndex;

BindProducts();

}

#endregion

#region "Event Handles"

protected void Page_Load(object sender, System.EventArgs e)

{

try

{

if (!IsPostBack)

{

//Default Submit Button

Page.Form.DefaultButton = cmdQuickSearch.UniqueID;

BindProducts();

}

catch

{

}

protected void cmdQuickSearch_Click(object sender, System.EventArgs e)

{

BindProducts();

}

protected void SupplierChanged(object sender, EventArgs e)

{

DropDownList ddlSupplier = (DropDownList)sender;

if (ddlSupplier != null)

{

ViewState["Filter_Supplier"] = ddlSupplier.SelectedValue;

}

BindProducts();

}

protected void CategoryChanged(object sender, EventArgs e)

{

DropDownList ddlCategory = (DropDownList)sender;

if (ddlCategory != null)

{

ViewState["Filter_Category"] = ddlCategory.SelectedValue;

}

BindProducts();

}

#endregion

}

VB.NET Code

Namespace FilterRecordsUsingDropDownListInHeaderTemplate

Public Class _Default

Inherits System.Web.UI.Page

#Region "ComboData"

Private Sub LoadDropDownList(ByVal ucControl As DropDownList, ByVal DataValueField As String, ByVal DataTextField As String, ByVal sql As String)

Dim objSQL As New SqlDataProvider

Dim objBind As DataTable = objSQL.FillTable(sql)

ucControl.Items.Clear()

If Not objBind Is Nothing Then

With ucControl

.DataTextField = DataTextField

.DataValueField = DataValueField

.DataSource = objBind

.DataBind()

End With

ucControl.Items.Insert(0, (New ListItem("---All---", "-1")))

End If

End Sub

#End Region

#Region "Bind Data"

Private Sub BindProducts()

Dim objBind As New DataTable

Dim iTotal As Integer = 0

Dim SupplierID As Integer = -1

Dim CategoryID As Integer = -1

If Not ViewState("Filter_Supplier") Is Nothing Then

SupplierID = ViewState("Filter_Supplier")

End If

If Not ViewState("Filter_Category") Is Nothing Then

CategoryID = ViewState("Filter_Category")

End If

objBind = BindData(txtSearch.Text, SupplierID, CategoryID)

If Not objBind Is Nothing Then

If objBind.Rows.Count > 0 Then

iTotal = objBind.Rows.Count

grvObject.DataSource = objBind

grvObject.DataBind()

trMessage.Visible = False

lblTotal.Visible = True

lblTotal.Text = "Total " & iTotal & " records"

Else

trMessage.Visible = True

lblTotal.Visible = False

grvObject.DataSource = New List(Of String)

grvObject.DataBind()

End If

updatePanel.Update()

End If

End Sub

Private Function BindData(ByVal Keyword As String, ByVal SupplierID As Integer, ByVal CategoryID As Integer) As DataTable

Dim objSQL As New SqlDataProvider

Dim objBind As DataTable = objSQL.FillTable("Pro_Products_List", New ObjectPara("@Keyword", Keyword.Trim), _

New ObjectPara("@SupplierID", SupplierID), _

New ObjectPara("@CategoryID", CategoryID))

Return objBind

End Function

#End Region

#Region "GridView Methods"

Private Sub grvObject_RowDataBound(ByVal sender As Object, ByVal e As System.Web.UI.WebControls.GridViewRowEventArgs) Handles grvObject.RowDataBound

If (e.Row.RowType = DataControlRowType.Header) Then

Dim sSQL As String = "Select distinct Suppliers.SupplierID, Suppliers.CompanyName From Products INNER JOIN Suppliers on Products.SupplierID = Suppliers.SupplierID"

Dim ddlSupplier As DropDownList = CType(e.Row.FindControl("ddlSupplier"), DropDownList)

If Not ddlSupplier Is Nothing Then

LoadDropDownList(ddlSupplier, "SupplierID", "CompanyName", sSQL)

If Not ViewState("Filter_Supplier") Is Nothing Then

ddlSupplier.Items.FindByValue(ViewState("Filter_Supplier").ToString()).Selected = True

End If

Dim ddlCategory As DropDownList = CType(e.Row.FindControl("ddlCategory"), DropDownList)

If Not ddlCategory Is Nothing Then

sSQL = "Select distinct Categories.CategoryID, Categories.CategoryName From Products INNER JOIN Categories on Products.CategoryID = Categories.CategoryID"

LoadDropDownList(ddlCategory, "CategoryID", "CategoryName", sSQL)

If Not ViewState("Filter_Category") Is Nothing Then

ddlCategory.Items.FindByValue(ViewState("Filter_Category").ToString()).Selected = True

End If

End Sub

Private Sub grvObject_PageIndexChanging(ByVal sender As Object, ByVal e As System.Web.UI.WebControls.GridViewPageEventArgs) Handles grvObject.PageIndexChanging

grvObject.PageIndex = e.NewPageIndex

BindProducts()

End Sub

#End Region

#Region "Event Handles"

Protected Sub Page_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Load

Try

If Page.IsPostBack = False Then

'Default Submit Button

Page.Form.DefaultButton = cmdQuickSearch.UniqueID

BindProducts()

End If

Catch ex As Exception

End Try

End Sub

Private Sub cmdQuickSearch_Click(ByVal sender As Object, ByVal e As System.EventArgs) Handles cmdQuickSearch.Click

BindProducts()

End Sub

Protected Sub SupplierChanged(ByVal sender As Object, ByVal e As EventArgs)

Dim ddlSupplier As DropDownList = DirectCast(sender, DropDownList)

If Not ddlSupplier Is Nothing Then

ViewState("Filter_Supplier") = ddlSupplier.SelectedValue

End If

BindProducts()

End Sub

Protected Sub CategoryChanged(ByVal sender As Object, ByVal e As EventArgs)

Dim ddlCategory As DropDownList = DirectCast(sender, DropDownList)

If Not ddlCategory Is Nothing Then

ViewState("Filter_Category") = ddlCategory.SelectedValue

End If

BindProducts()

End Sub

#End Region

End Class

End Namespace

Bây giờ chạy Project bạn sẽ có kết quả như ảnh phía dưới.

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