Change the color of a row or record on a gridview on asp.net c#?

Question

I am making a table for an appointment book... and I need to do the following...

Display all appointments that have not been attended yet (I have a button to mark them as attended)... If an appointment has not been attended and it's date is before today's date, that row must appear in red (the text font color)...

So my questions are, how do I change the color of specific rows, AND if there's something that I must get in the query to specify that this row has to have a differente color?

Thank You

<asp:GridView ID="grdvEventosVendedor" runat="server" AllowPaging="True" 
                AutoGenerateColumns="False" CellPadding="4" DatakeyNames="idCita"
                EmptyDataText="No Hay Eventos Para Este Vendedor" ForeColor="#333333" 
                GridLines="None" AllowSorting="True"
                onpageindexchanging="grdvEventosVendedor_PageIndexChanging" 
                onrowcommand="grdvEventosVendedor_RowCommand" 
                onsorting="grdvEventosVendedor_Sorting" CellSpacing="1" 
                onrowdatabound="grdvEventosVendedor_RowDataBound" >
                <AlternatingRowStyle BackColor="White" ForeColor="#284775"/>

                <Columns>
                    <asp:TemplateField HeaderText="" ItemStyle-Width="35px">
                        <ItemTemplate>
                            <asp:ImageButton ID="imgBtnEdicEvento" runat="server" 
                                CommandArgument='<%# Eval("idCita")%>' CommandName="Edicion" 
                                Height="32px" ImageUrl="~/img/pencil_32.png" Width="32px" />
                        </ItemTemplate>
                    </asp:TemplateField>

                    <asp:TemplateField HeaderText="" ItemStyle-Width="35px">
                        <ItemTemplate>
                            <asp:ImageButton ID="imgBtnDelete" runat="server"
                                CommandName="Borrar" 
                                ImageUrl="~/img/1385_Disable_16x16_72.png" 
                                onclientclick="return confirm('¿Desea eliminar el registro?');" 
                                CommandArgument='<%# Eval("idCita")%>' />
                        </ItemTemplate>
                    </asp:TemplateField>

                    <asp:BoundField DataField="Cliente" HeaderText="Cliente" InsertVisible="False" ReadOnly="True" SortExpression="Cliente" ItemStyle-Width="50px" />
                    <asp:BoundField DataField="Empresa" HeaderText="Empresa" InsertVisible="False" ReadOnly="True" SortExpression="Empresa" ItemStyle-Width="50px"/>
                    <asp:BoundField DataField="Telefono" HeaderText="Telefono" InsertVisible="False" ReadOnly="True" SortExpression="Telefono" ItemStyle-Width="50px"/>
                    <asp:BoundField DataField="Nextel" HeaderText="Nextel" InsertVisible="False" ReadOnly="True" SortExpression="Nextel" ItemStyle-Width="50px"/>
                    <asp:BoundField DataField="Tipo" HeaderText="Tipo" InsertVisible="False" ReadOnly="True" SortExpression="Tipo" ItemStyle-Width="50px"/>
                    <asp:BoundField DataField="Descripcion" HeaderText="Descripcion" InsertVisible="False" ReadOnly="True" SortExpression="Descripcion" ItemStyle-Width="100px"/>

                    <asp:TemplateField HeaderText="Fecha" SortExpression="Fecha" ItemStyle-Width="50px">
                        <ItemTemplate>                                            
                            <%# DataBinder.Eval(Container.DataItem, "Fecha", "{0:dd/MM/yyyy}")%>
                        </ItemTemplate>

                        <EditItemTemplate>                                        
                            <asp:TextBox ID="tbxFecha"  runat="server" Text='<%#Bind("Fecha","{0:dd/MM/yyyy}") %>' ValidationGroup="gpEdicionAgenda">
                            </asp:TextBox>
                        </EditItemTemplate>
                    </asp:TemplateField>

                    <asp:BoundField DataField="HoraInicio" HeaderText="Hora" InsertVisible="False" ReadOnly="True" SortExpression="HoraInicio" ItemStyle-Width="50px"/>
                    <asp:BoundField DataField="Lugar" HeaderText="Lugar" InsertVisible="False" ReadOnly="True" SortExpression="Lugar" ItemStyle-Width="50px"/>
                    <asp:BoundField DataField="Estado" HeaderText="Estado" InsertVisible="False" ReadOnly="True" SortExpression="Estado" ItemStyle-Width="50px"/>

                    <asp:TemplateField HeaderText="Atender" ItemStyle-Width="35px">
                        <ItemTemplate>
                            <asp:ImageButton ID="imgBtnAtender" runat="server"
                                CommandArgument='<%# Eval("idCita")%>' CommandName="Atender" 
                                ImageUrl="~/img/activar.png" Width="16px" Height="16px" 
                                onclientclick="return confirm('¿Desea marcar como atendido este registro?');" />
                        </ItemTemplate>
                    </asp:TemplateField>

                    <asp:TemplateField HeaderText="CRM" ItemStyle-Width="35px">
                        <ItemTemplate>
                            <asp:ImageButton ID="imgBtnCRM" runat="server"
                                CommandArgument='<%# Eval("IdCliente")%>' CommandName="CRM" 
                                ImageUrl="~/img/go.gif" Width="16px" Height="16px" />
                        </ItemTemplate>
                    </asp:TemplateField>

                    <asp:TemplateField HeaderText="VM" ItemStyle-Width="35px">
                        <ItemTemplate>
                            <asp:ImageButton ID="imgBtnVerMas" runat="server"
                                CommandArgument='<%# Eval("IdCliente")%>' CommandName="VerMas" 
                                ImageUrl="~/img/search.png" Width="16px" Height="16px" />
                        </ItemTemplate>
                    </asp:TemplateField>
                </Columns>

                <EditRowStyle BackColor="#999999" Font-Size="Small" />
                <FooterStyle BackColor="#5D7B9D" Font-Bold="True" ForeColor="White" />
                <HeaderStyle BackColor="#5D7B9D" Font-Bold="True" ForeColor="White" Font-Size="Larger" />
                <PagerStyle BackColor="#284775" ForeColor="White" HorizontalAlign="Center" />
                <RowStyle BackColor="#F7F6F3" ForeColor="#333333" HorizontalAlign="Center" Font-Size="Small" />
                <SelectedRowStyle BackColor="#E2DED6" Font-Bold="True" ForeColor="#333333" />
                <SortedAscendingCellStyle BackColor="#E9E7E2" />
                <SortedAscendingHeaderStyle BackColor="#506C8C" />
                <SortedDescendingCellStyle BackColor="#FFFDF8" />
                <SortedDescendingHeaderStyle BackColor="#6F8DAE" />
            </asp:GridView>

Answer 1

You can change the color of row by specifying your color in Backcolor attribute of row which you can specify in grdvEventosVendedor_RowDataBound event of gridview

 e.Row.BackColor = Drawing.Color.Red;

or, you can use

`e.Row.BackColor = Color.FromName("#FFOOOO");` 

You can do like this to implement above things:

protected void grdvEventosVendedor_RowDataBound(object sender, GridViewRowEventArgs e)
{
  if (e.Row.RowType = DataControlRowType.DataRow)
  {
      if(put_your_condition_here)
      {
           e.Row.BackColor = Drawing.Color.Red;
           //// or you can assign color by doing this: e.Row.BackColor = Color.FromName("#FFOOOO");
      }
  }
}

Answer 2

There are a number of ways to handle this, including looping through each row after data-binding (or) during the RowDataBound event:

foreach (GridViewRow row in yourGridView.Rows)
{
    // Find controls/data to do comparison against
    e.Row.BackColor = Color.FromName("#FF0000"); 
}

Or...

protected void yourGridView_RowDataBound(object sender, GridViewRowEventArgs e)
{
    // Watch out for header and footer rows here
    e.Row.BackColor = Color.FromName("#FF0000");                
}