Highlight Gridview Row Using C#

Here I have created sample that will help you out.

HTML

<div>
    <style type="text/css">
        .Lime
        {
            background-color: Lime;
        }
    </style>
    Number :
    <asp:TextBox ID="txtNumber" runat="server" AutoPostBack="true" OnTextChanged="TextChanged" />
    <br />
    <br />
    <asp:GridView ID="GridView1" CssClass="Grid" runat="server" OnRowDeleting="OnRowDeleting"
        AutoGenerateColumns="false" OnRowDataBound="OnRowDataBound">
        <Columns>
            <asp:BoundField DataField="Item" HeaderText="Item" />
            <asp:BoundField DataField="Price" HeaderText="Price" />
            <asp:CommandField ShowDeleteButton="True" ButtonType="Button" />
        </Columns>
    </asp:GridView>
</div>

C#

protected void Page_Load(object sender, EventArgs e)
{
    if (!Page.IsPostBack)
    {
        DataTable dt = new DataTable();
        dt.Columns.AddRange(new DataColumn[2] { new DataColumn("Item"), new DataColumn("Price") });
        dt.Rows.Add("Shirt", 450);
        dt.Rows.Add("Jeans", 3200);
        dt.Rows.Add("Trousers", 1900);
        dt.Rows.Add("Tie", 185);
        dt.Rows.Add("Cap", 100);
        ViewState["dt"] = dt;
        BindGrid();
    }
}

protected void BindGrid()
{
    GridView1.DataSource = ViewState["dt"] as DataTable;
    GridView1.DataBind();
}

protected void OnRowDeleting(object sender, GridViewDeleteEventArgs e)
{
    int index = Convert.ToInt32(e.RowIndex);
    DataTable dt = ViewState["dt"] as DataTable;
    dt.Rows[index].Delete();
    ViewState["dt"] = dt;
    BindGrid();
}

protected void TextChanged(object sender, EventArgs e)
{
    foreach (GridViewRow row in GridView1.Rows)
    {
        SetLime(row);
    }
}

protected void OnRowDataBound(object sender, GridViewRowEventArgs e)
{
    if (e.Row.RowType == DataControlRowType.DataRow)
    {
        string item = e.Row.Cells[0].Text;
        foreach (Button button in e.Row.Cells[2].Controls.OfType<Button>())
        {
            if (button.CommandName == "Delete")
            {
                button.Attributes["onclick"] = "if(!confirm('Do you want to delete " + item + "?')){ return false; };";
            }
        }
        SetLime(e.Row);
    }
}

private void SetLime(GridViewRow row)
{
    if (row.RowType == DataControlRowType.DataRow)
    {
        if (!string.IsNullOrEmpty(txtNumber.Text))
        {
            if (row.RowIndex >= Convert.ToInt32(txtNumber.Text))
            {
                row.CssClass = "Lime";
            }
            else
            {
                row.CssClass = "";
            }
        }
    }
}

Screenshot