Arrange controls Horizontally in Bootstrap

Here I have created a sample, which doesn't breaks the alignment of textbox with Bootstrap.

HTML

    <div class="row">
        <div class="col-md-2 text-right col-last">
            Search By :
        </div>
        <div class="col-md-2 col-last">
            <asp:DropDownList ID="ddlStatus" runat="server" CssClass="form-control">
                <asp:ListItem Text="ID" Value="1" />
                <asp:ListItem Text="Type" Value="2" />
                <asp:ListItem Text="Status" Value="3" />
                <asp:ListItem Text="Date" Value="4" />
            </asp:DropDownList>
        </div>
        <div class="col-md-2 col-last">
            <asp:TextBox ID="txtSearch" runat="server" placeholder="Search" CssClass="form-control"></asp:TextBox>
        </div>
        <div class="col-md-2">
            <asp:LinkButton ID="btnSearch" runat="server" CssClass="btn btn-blue" Text="Search"></asp:LinkButton>
        </div>
    </div>

Screenshot