Q:

How to repeat with repeater for 10 times the same code?

<asp:Repeater id="rptExcelField" runat="server">
    <HeaderTemplate>
        <table style="width:100%;" id="mainTable">
    </HeaderTemplate>         
    <ItemTemplate>
        <tr>
            <td class="style1">
                <asp:Label ID="lblField" runat="server" Text="Polje:" CssClass="textType"></asp:Label>
            </td>                
            <td class="style2">
                <asp:TextBox ID="txtField" runat="server" Width="436px" MaxLength="45" 
                    CssClass="inputType"></asp:TextBox>
                <asp:DropDownList ID="ddlInputType" runat="server" oninit="ddlInputType_Init" 
                    AutoPostBack="True" 
                    onselectedindexchanged="ddlInputType_SelectedIndexChanged">                        
                </asp:DropDownList>     
            </td>
            <td class="style3">
                <asp:RequiredFieldValidator ID="rfvName" runat="server" ControlToValidate="txtName"
                    ErrorMessage="*" CssClass="validator"></asp:RequiredFieldValidator>
            </td>
        </tr>
    </ItemTemplate>         
    <FooterTemplate>
        </table>
    </FooterTemplate>         

How to repeat with repeater for 10 times the same code?

A:

Realistically, you just need to bind the repeater to something with 10 items in it. Maybe not the best approach to simply dump 10 iterations on screen, but to answer your question specifically:
Code-behind:
protected void Page_Load(object sender, EventArgs e)
{
    List<int> data = new List<int>();
    for(int i=0; i<10; i++)
    {
        data.Add(i);
    }

    rptExcelField.DataSource = data;
    rptExcelField.DataBind();
}

