How to select multiple records from GridView and retrieve selected records value?

Introduction

GridvIew control is a powerful data grid control that allows us to display the data in tabular format with sorting and pagination. It also allows us to manipulate the data.

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To demonstrate this example, we are going to create a demo web page and my GridView code looks like below.

ASPX PAGE

<asp:GridView ID="GridView1" runat="server" AutoGenerateColumns="false" AllowPaging="true"
DataKeyNames="AutoId" OnPageIndexChanging="PaginateTheData" EnablePersistedSelection="true"
PageSize="5" PagerSettings-Mode="Numeric">
<Columns>
<asp:TemplateField HeaderText="Select">
<ItemTemplate>
<asp:CheckBox ID="chkSelect" runat="server" />
</ItemTemplate>
</asp:TemplateField>
<asp:BoundField HeaderText="AutoId" DataField="AutoId" />
<asp:BoundField HeaderText="First Name" DataField="FirstName" />
<asp:BoundField HeaderText="Last Name" DataField="LastName" />
<asp:TemplateField HeaderText="Is Active?">
<ItemTemplate>
<%# Eval("Active").ToString().Equals("True") ? "Yes" : "No" %>
</ItemTemplate>
</asp:TemplateField>
</Columns>
</asp:GridView>
<p><asp:Button ID="btnGetSelected" runat="server" Text="Get Selected Records" OnClick="GetSelectedRecords" /></p>

In the above code snippet, on the .aspx page we have a GridView with asp:BoundField & asp:TemplateField (this is used to display the column data in the format we want or is used to display custom data. In this case we have displayed a CheckBox as the first column and Yes/No as the last column based on Active column value from the database). We have set AutoId (primary key of the table) as the DataKeyNames that we will use to identify the selected row of the GridView.

CODE BEHIND

string _connStr = ConfigurationManager.ConnectionStrings["ConnStr"].ConnectionString;
protected void Page_Load(object sender, EventArgs e)
{
if (!IsPostBack)
{
this.GetData();
}
}
/// <summary>
/// Paginates the data.
/// </summary>
/// <param name="sender">The sender.</param>
/// <param name="e">The <see cref="System.Web.UI.WebControls.GridViewPageEventArgs"/>instance containing the event data.</param>
protected void PaginateTheData(object sender, GridViewPageEventArgs e)
{
GridView1.PageIndex = e.NewPageIndex;
this.GetData();
}

private void GetData()
{
DataTable table = new DataTable();
// get the connection
using (SqlConnection conn = new SqlConnection(_connStr))
{
// write the sql statement to execute
string sql = "SELECT AutoId, FirstName, LastName, Age, Active FROMPersonalDetail ORDER By AutoId";
// instantiate the command object to fire
using (SqlCommand cmd = new SqlCommand(sql, conn))
{
// get the adapter object and attach the command object to it
using (SqlDataAdapter ad = new SqlDataAdapter(cmd))
{
// fire Fill method to fetch the data and fill into DataTable
ad.Fill(table);
}
}
}
GridView1.DataSource = table;
GridView1.DataBind();
}

/// <summary>
/// Gets the selected records.
/// </summary>
/// <param name="sender">The sender.</param>
/// <param name="e">The <see cref="System.EventArgs"/> instance containing the event data.</param>
protected void GetSelectedRecords(object sender, EventArgs e)
{
Response.Write("<h3>Selected records</h3>");
foreach (GridViewRow row in GridView1.Rows)
{
CheckBox chk = (CheckBox)row.FindControl("chkSelect");
if (chk.Checked)
{
// get the selected AutoId and cells text
Response.Write("AutoId: " + GridView1.DataKeys[row.RowIndex].Value + ", First Name: " + row.Cells[2].Text + "<br />");
}
}
}

The button fires GetSelectedRecords server side method, in which we have looped through all the rows of the GridView and found the CheckBox using FindControl method. In case the checkbox is checked by the user, we have retrieved the DataKey value of that row as well as the FirstName of that records (by retrieving 3rd cell text of that row).

Note: In this case, the selection is not maintained if user navigates to another page (this issue has been resolved in the next article, I will be publishing soon)

OUTPUT