comment puis-je faire ma gridview pour s'adapter à 100% à la page

Comment puis-je faire ma gridview pour s'intégrer parfaitement à l'intérieur de l'écran.
J'ai ajouté cette propriété width="100%" je me. Cependant mon gridview toujours s'étend bien au-delà de l'en-tête de la largeur que j'ai comme 100%.

Voici mon code source de mon gridview pour la première tentative.

<asp:GridView ID="GWCase" runat="server"  Top="0%" Width="100%" BackColor="#CCCCCC" BorderColor="#999999" BorderStyle="Solid" BorderWidth="3px" CellPadding="4" CellSpacing="2" ForeColor="Black" Height="199px" AutoGenerateSelectButton="True" OnSelectedIndexChanged="GWCase_SelectedIndexChanged">

    <FooterStyle BackColor="#CCCCCC" />
    <HeaderStyle BackColor="Black" Font-Bold="True" ForeColor="White" />
    <PagerStyle BackColor="#CCCCCC" ForeColor="Black" HorizontalAlign="Left" />
    <RowStyle BackColor="White" />
    <SelectedRowStyle BackColor="#000099" Font-Bold="True" ForeColor="White" />
    <SortedAscendingCellStyle BackColor="#F1F1F1" />
    <SortedAscendingHeaderStyle BackColor="#808080" />
    <SortedDescendingCellStyle BackColor="#CAC9C9" />
    <SortedDescendingHeaderStyle BackColor="#383838" />
</asp:GridView>

J'ai essayé d'utiliser la méthode css comme ceci

<ul id="assigngw">
<asp:GridView ID="GWCase" runat="server"  Top="0%" BackColor="#CCCCCC" BorderColor="#999999" BorderStyle="Solid" BorderWidth="3px" CellPadding="4" CellSpacing="2" ForeColor="Black" Height="199px" AutoGenerateSelectButton="True" OnSelectedIndexChanged="GWCase_SelectedIndexChanged">

    <FooterStyle BackColor="#CCCCCC" />
    <HeaderStyle BackColor="Black" Font-Bold="True" ForeColor="White" />
    <PagerStyle BackColor="#CCCCCC" ForeColor="Black" HorizontalAlign="Left" />
    <RowStyle BackColor="White" />
    <SelectedRowStyle BackColor="#000099" Font-Bold="True" ForeColor="White" />
    <SortedAscendingCellStyle BackColor="#F1F1F1" />
    <SortedAscendingHeaderStyle BackColor="#808080" />
    <SortedDescendingCellStyle BackColor="#CAC9C9" />
    <SortedDescendingHeaderStyle BackColor="#383838" />
</asp:GridView>
    </ul>

Code Css :

#assigngw {
width:100%;
}

Malheureusement les deux ne fonctionne pas.

Voici mon code source complet.

<asp:Content ID="Content1" ContentPlaceHolderID="ContentPlaceHolder1" runat="server">
<link rel="stylesheet" href="css/style.css" type="text/css" />
<asp:ScriptManager ID="ScriptManager1" runat="server">
</asp:ScriptManager>
<asp:UpdatePanel ID="UpdatePanel1" runat="server">
<ContentTemplate>
<ul id="assigngw">
<asp:GridView ID="GWCase" runat="server" width="300px" Top="0%" BackColor="#CCCCCC" BorderColor="#999999" BorderStyle="Solid" BorderWidth="3px" CellPadding="4" CellSpacing="2" ForeColor="Black" Height="199px" AutoGenerateSelectButton="True" OnSelectedIndexChanged="GWCase_SelectedIndexChanged">
<FooterStyle BackColor="#CCCCCC" />
<HeaderStyle BackColor="Black" Font-Bold="True" ForeColor="White" />
<PagerStyle BackColor="#CCCCCC" ForeColor="Black" HorizontalAlign="Left" />
<RowStyle BackColor="White" />
<SelectedRowStyle BackColor="#000099" Font-Bold="True" ForeColor="White" />
<SortedAscendingCellStyle BackColor="#F1F1F1" />
<SortedAscendingHeaderStyle BackColor="#808080" />
<SortedDescendingCellStyle BackColor="#CAC9C9" />
<SortedDescendingHeaderStyle BackColor="#383838" />
</asp:GridView>
</ul>
<br />
Case ID :
<asp:Label ID="lblCID" runat="server"></asp:Label>
&nbsp;is situation near
<asp:DropDownList ID="lblocation" runat="server" OnSelectedIndexChanged="lblocation_SelectedIndexChanged" AutoPostBack="True" DataTextField="location" DataValueField="location">
<asp:ListItem>Select Location</asp:ListItem>
<asp:ListItem>Bukit Batok NPC</asp:ListItem>
<asp:ListItem>Bukit Panjang NPC</asp:ListItem>
<asp:ListItem>Choa Chu Kang NPC</asp:ListItem>
<asp:ListItem>Jurong West NPC</asp:ListItem>
<asp:ListItem>Nanyang NPC</asp:ListItem>
<asp:ListItem>Woodlands East NPC</asp:ListItem>
<asp:ListItem>Woodlands West NPC</asp:ListItem>
<asp:ListItem>Ang Mo Kio North NPC</asp:ListItem>
<asp:ListItem>Ang Mo Kio South NPC</asp:ListItem>
<asp:ListItem>Punggol NPC</asp:ListItem>
<asp:ListItem>Hougang NPC</asp:ListItem>
<asp:ListItem>Sembawang NPC</asp:ListItem>
<asp:ListItem>Serangoon NPC</asp:ListItem>
<asp:ListItem>Sengkang NPC</asp:ListItem>
<asp:ListItem>Yishun North NPC</asp:ListItem>
<asp:ListItem>Yishun South NPC</asp:ListItem>
<asp:ListItem>Bedok North NPC</asp:ListItem>
<asp:ListItem>Bedok South NPC</asp:ListItem>
<asp:ListItem>Changi NPC</asp:ListItem>
<asp:ListItem>Geylang NPC</asp:ListItem>
<asp:ListItem>Marine Parade NPC</asp:ListItem>
<asp:ListItem>Pasir Ris NPC</asp:ListItem>
<asp:ListItem>Tampines NPC</asp:ListItem>
<asp:ListItem>Bukit Merah West NPC</asp:ListItem>
<asp:ListItem>Clementi NPC</asp:ListItem>
<asp:ListItem>Queenstown NPC</asp:ListItem>
<asp:ListItem>Jurong East NPC</asp:ListItem>
<asp:ListItem>Bishan NPC</asp:ListItem>
<asp:ListItem>Bukit Timah NPC</asp:ListItem>
<asp:ListItem>Kampung Java NPC</asp:ListItem>
<asp:ListItem>Orchard NPC</asp:ListItem>
<asp:ListItem>Toa Payoh NPC</asp:ListItem>
<asp:ListItem>Bukit Merah East NPC</asp:ListItem>
<asp:ListItem>Rochor NPC</asp:ListItem>
<asp:ListItem>Marina Bay NPC</asp:ListItem>
</asp:DropDownList>
<br />
<br />
The following case will be assigned to this selected officer&nbsp;
<asp:DropDownList ID="DDLpolice" runat="server" DataTextField="dropdownpolice" DataValueField="dropdownpolice" OnSelectedIndexChanged ="DDLpolice_SelectedIndexChanged1" style="height: 22px"
AppendDataBoundItems="true" AutoPostBack="True">
<asp:ListItem Value="-1">Select Officer</asp:ListItem>
</asp:DropDownList>