Search into Textbox and Bind Gridview using Asp.net

Design page for Gridview and textbox :

<div> Enter first name to search: </div> <div> <asp:TextBox ID="txtSearch" runat="server" AutoPostBack="true" OnTextChanged="txtSearch_TextChanged"> </asp:TextBox>&nbsp; </div> <div> <asp:UpdatePanel ID="updatepanel1" runat="server"> <ContentTemplate> <asp:GridView ID="grdSearch" runat="server" AutoGenerateColumns="false"> <Columns> <asp:TemplateField HeaderText="Employee Id"> <ItemTemplate> <asp:Label ID="lblFirstName" runat="server" Text='<%# Highlight(Eval("emp_id").ToString()) %>'> </asp:Label> </ItemTemplate> </asp:TemplateField> <asp:TemplateField HeaderText="Employee First Name"> <ItemTemplate> <asp:Label ID="lblLastName" runat="server" Text='<%#(Eval("emp_first_name")) %>'></asp:Label> </ItemTemplate> </asp:TemplateField> <asp:TemplateField HeaderText="Employee Middle Name"> <ItemTemplate> <asp:Label ID="lblLocation" runat="server" Text='<%#(Eval("emp_middle_name")) %>'></asp:Label> </ItemTemplate> </asp:TemplateField> <asp:TemplateField HeaderText="Employee Last Name"> <ItemTemplate> <asp:Label ID="lblLocation" runat="server" Text='<%#(Eval("emp_last_name")) %>'></asp:Label> </ItemTemplate> </asp:TemplateField> <asp:TemplateField HeaderText="Employee Name"> <ItemTemplate> <asp:Label ID="lblLocation" runat="server" Text='<%#(Eval("emp_name")) %>'></asp:Label> </ItemTemplate> </asp:TemplateField> </Columns> </asp:GridView> </ContentTemplate> <Triggers> <asp:AsyncPostBackTrigger ControlID="txtSearch" EventName="TextChanged" /> </Triggers> </asp:UpdatePanel> </div>

Code for This page :

string strConnection = "Data Source=BITPLUS3\\SqlExpress;Initial Catalog=HRDB;User ID=sa;pwd=bit123"; //ConfigurationManager.AppSettings["WebHRConnectionString"]; protected void Page_Load(object sender, EventArgs e) { if (!IsPostBack) { // BindGrid(); } } private DataTable GetRecords() { SqlConnection conn = new SqlConnection(strConnection); conn.Open(); SqlCommand cmd = new SqlCommand(); cmd.Connection = conn; cmd.CommandType = CommandType.Text; cmd.CommandText = "Select emp_id, emp_first_name, emp_middle_name,emp_last_name, emp_name from tblemployee"; SqlDataAdapter dAdapter = new SqlDataAdapter(); dAdapter.SelectCommand = cmd; DataSet objDs = new DataSet(); dAdapter.Fill(objDs); return objDs.Tables[0]; } private void BindGrid() { DataTable dt = GetRecords(); if (dt.Rows.Count > 0) { grdSearch.DataSource = dt; grdSearch.DataBind(); } } private void SearchText() { DataTable dt = GetRecords(); DataView dv = new DataView(dt); string SearchExpression = null; if (!String.IsNullOrEmpty(txtSearch.Text)) { SearchExpression = string.Format("{0} '%{1}%'", grdSearch.SortExpression, txtSearch.Text); } dv.RowFilter = "emp_name like" + SearchExpression; grdSearch.DataSource = dv; grdSearch.DataBind(); } public string Highlight(string InputTxt) { string Search_Str = txtSearch.Text.ToString(); // Setup the regular expression and add the Or operator. Regex RegExp = new Regex(Search_Str.Replace(" ", "|").Trim(), RegexOptions.IgnoreCase); // Highlight keywords by calling the //delegate each time a keyword is found. return RegExp.Replace(InputTxt, new MatchEvaluator(ReplaceKeyWords)); // Set the RegExp to null. RegExp = null; } public string ReplaceKeyWords(Match m) { return "<span class=highlight>" + m.Value + "</span>"; } protected void txtSearch_TextChanged(object sender, EventArgs e) { SearchText(); }