Hi simflex,

Refer below link and sample.

Change Background color of GridView Row using RowDataBound event in ASP.Net using C# and VB.Net

HTML

<asp:GridView ID="gvCustomers" runat="server" AutoGenerateColumns="false" 
    onrowdatabound="gvCustomers_RowDataBound">
    <Columns>
        <asp:BoundField DataField="CustomerId" HeaderText="Id" />
        <asp:BoundField DataField="Name" HeaderText="Name" />
        <asp:TemplateField>
            <ItemTemplate>
                <asp:HyperLink runat="server" NavigateUrl="~/CS.aspx" ID="HyperLink1" Text="Listen" />
            </ItemTemplate>
        </asp:TemplateField>
    </Columns>
</asp:GridView>

Namespaces

C#

using System.Data;
using System.Drawing;

Code

C#

protected void Page_Load(object sender, EventArgs e)
{
    if (!this.IsPostBack)
    {
        DataTable dt = new DataTable();
        dt.Columns.AddRange(new DataColumn[] { new DataColumn("CustomerId", typeof(int)), new DataColumn("Name", typeof(string)) });
        dt.Rows.Add(1, "Mudassar Khan");
        dt.Rows.Add(2, "John Hammod");
        dt.Rows.Add(3, "Rober");
        dt.Rows.Add(1, "Suzzain");
        this.gvCustomers.DataSource = dt;
        this.gvCustomers.DataBind();
    }
}

protected void gvCustomers_RowDataBound(object sender, GridViewRowEventArgs e)
{
    if (e.Row.RowType == DataControlRowType.DataRow)
    {
        if (e.Row.Cells[0].Text == "1")
        {
            e.Row.Cells[2].BackColor = Color.Red;
        }
    }
}

Screenshot