Grid view, button, textbox bootstrap class in visual studio asp.net C#

 <asp:GridView ID="GridView1" runat="server" DataSourceID="SqlDataSource1" 

        AutoGenerateColumns="False" DataKeyNames="ID" CssClass="table table-striped table-bordered table-condensed">

</asp:GridView>

reference = https://dotnetgenetics.blogspot.com/2014/09/aspnet-gridview-control-crud-with.html

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Bootstrap buttons

<asp:Button runat="server" ID="btnSave" Text="Save" class="btn" />

    <asp:Button runat="server" ID="btnSave1" Text="Save" class="btn btn-default" />

reference = https://www.w3schools.com/bootstrap/bootstrap_buttons.asp    

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Bootstrap label and textbox

    <div class="form-group">

        <asp:Label runat="server" ID="lblName" Text="Name" AssociatedControlID="txtName" />

        <asp:TextBox runat="server" ID="txtName" class="form-control" />

    </div>

reference:- https://www.w3schools.com/bootstrap/bootstrap_forms_sizing.asp

Note:- Also you have to use default master page in asp.net application

<%@ Page Title="About" Language="C#" MasterPageFile="~/Site.Master" AutoEventWireup="true" CodeFile="Grid.aspx.cs" Inherits="About" %>

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

--------------------your code here ---------------------------

</asp:Content>