Please Check an Below Code for your Referance.
.aspx Page
On Datalist OnItemcommand Event we check the value
OnItemCommand="dlList_ItemCommand"
<form id="form1" runat="server">
<div>
<asp:Label ID="lblIdDisplay" runat="server" Text=""></asp:Label>
<asp:DataList ID="dlList" runat="server" RepeatLayout="Table" RepeatColumns="1" OnItemCommand="dlList_ItemCommand">
<ItemTemplate>
<table cellpadding="1" cellspacing="0" style="width: 500px; height: 100px; border: dashed 2px green;
background-color: #C2D69B">
<tr>
<td>
<asp:LinkButton ID="lnkId" Text='<%#Eval("EmployeeID") %>' runat="server">
</asp:LinkButton>
</td>
<td>
<%#Eval("FirstName")%>
</td>
<td>
<%#Eval("LastName")%>
</td>
</tr>
</table>
</ItemTemplate>
</asp:DataList>
</div>
</form>
In .cs code
protected void Page_Load(object sender, EventArgs e)
{
if(!this.IsPostBack)
{
this.BindDataList();
}
}
private void BindDataList()
{
string strConnString = ConfigurationManager.ConnectionStrings["constr"].ConnectionString;
SqlConnection con = new SqlConnection(strConnString);
SqlCommand cmd = new SqlCommand("SELECT EmployeeID,FirstName,LastName FROM Employees ");
SqlDataAdapter sda = new SqlDataAdapter();
cmd.Connection = con;
sda.SelectCommand = cmd;
DataSet ds = new DataSet();
sda.Fill(ds);
dlList.DataSource = ds;
dlList.DataBind();
}
protected void dlList_ItemCommand(object source, DataListCommandEventArgs e)
{
/* declaring variable as integer Type to store Id value in i */
int i;
/* select an row index where you selected Id */
int index = Convert.ToInt32(e.Item.ItemIndex);
/*To get and Link Button Form selected row*/
LinkButton lnkId = (LinkButton)e.Item.FindControl("lnkId");
/* Assigning selected Id Value to Display in Label */
lblIdDisplay.Text = lnkId.Text;
/* If you want to store selected Id value in i variable */
i = Convert.ToInt32(lnkId.Text);
}