请教.formview findcontrol 並未將物件參考設定為物件的執行個體

Question

<asp:FormView ID="FormView1" runat="server" AllowPaging="true" Width="552px" >
                    <ItemTemplate>
                    <table width="100%" border="0" cellspacing="0" cellpadding="3">
                      <tr>
                        <td class="contenttext" style="height: 20px; width: 468px;"> <p>&nbsp;</p>
                          <p><span class="contenttext"><b><%# Eval("building") %></b></span><br />
                              <span class="contenttext"><%# Eval("addr") %></span></p></td>
                          <td class="contenttext" style="height: 20px" valign="top" align="right">
                              <a href="pro_print.aspx?b=<%# Eval("building") %>&r=<%=Request.QueryString["r"] %>"><img src="images/print.gif" border="0"  /></a></td>
                        </tr>
                    </table>
                    <table width="100%" border="0" cellspacing="0" cellpadding="3">
                      <tr>
                        <td colspan="2" valign="top" style="height: 19px"><hr size="1" noshade="noshade" /></td>
                        </tr>
                      <tr>
                        <td valign="top" class="photo">                            <asp:FormView ID="FormView2" runat="server">
                                <ItemTemplate>
                                 <table width="291" border="0" cellspacing="0" cellpadding="0">
                                    <tr>
                                   
                                    <img id="zoom" src="readimg.aspx?id=<%# Eval("p_id") %>&ref=<%# Eval("ref") %>" width="291" height="232" alt="" /> 
                                    </tr>
                               </table>
                                </ItemTemplate>
                            </asp:FormView>
                               <asp:DataList ID="DataList1" runat="server" RepeatColumns="5" RepeatDirection="Horizontal">
                                <ItemTemplate>
                                <table border="0" cellspacing="0" cellpadding="0" style="width: 56px">
                                    <tr>
                                      <td>                                      <img src='readimg.aspx?id=<%# Eval("p_id")  %>&ref=<%# Eval("ref")%> 'width="55" height="52" onclick="document.getElementById('zoom').src=this.src" style="cursor:pointer;" />
    
                                      </td>
                                    </tr>
                                  </table>  
                                </ItemTemplate>
                            </asp:DataList>
                        
                          <hr align="left" width="291" size="1" noshade="noshade" />
                          <table width="291" border="0" cellspacing="0" cellpadding="3">
                            <tr>
                              <td colspan="2" class="contenttext"><strong>Enquire about this property<br /></strong></td>
                            </tr>
                            <tr>
                              <td width="169"><input name="textfield" type="text" class="formbox" value="Name" /></td>
                              <td>&nbsp;</td>
                            </tr>
                            <tr>
                              <td width="169"><input name="textfield4" type="text" class="formbox" value="Phone Number" /></td>
                              <td>&nbsp;</td>
                            </tr>
                            <tr>
                              <td width="169"><input name="textfield5" type="text" class="formbox" value="Email" /></td>
                              <td><a href="#"><img src="images/but_submit.gif" width="50" height="19" border="0" id="Image8" onmouseover="MM_swapImage('Image8','','images/but_submit_h.gif',1)" onmouseout="MM_swapImgRestore()" alt="" /></a></td>
                            </tr>
                            <tr>
                              <td>&nbsp;</td>
                              <td>&nbsp;</td>
                            </tr>
                            <tr>
                              <td colspan="2" class="contenttext"><strong>Contact Us</strong><br />
                                Leasing Department<br />
                                852-2822-6800<br />
                                  <span class="propertyblue"><a href="mailto:[email protected]">[email protected]</a><br />
                                  <br />
                                  <a href="search_result.aspx?keyword=<%# Eval("building") %>">Search other units in this building</a></span></td>
                            </tr>
                          </table>                          
                          <p>&nbsp;</p></td>
                        <td width="210" valign="top"><p class="property"><strong>High-rise apartments<br />HK$<%# Eval("rental", "{0:0,0}")%> 
                            <asp:Label ID="Label1" runat="server" Text="inclusive per month" Visible='<%# (bool)(Eval("mgmt").ToString()=="999999") %>'></asp:Label></strong></p>
                          <p class="property"><strong>Layout</strong><br />
                            Size: <%# Eval("area", "{0:0,0}")%> sq ft<br />
                            <%# Eval("bedrooms") %> Bedroom<br />
                            <%# Eval("bathrooms") %> Bathroom</p>
                          <p class="property"><strong>Property Description</strong><br />
                             <%# Eval("property_desc") %></p>                          <p class="property"><strong>Facilities </strong>
                          <%# Eval("fac1") %>
                          <%# Eval("fac2") %>
                          <%# Eval("fac3") %></p>
                          
                          <p class="property"><strong>Enquire about this property</strong><br />
                            Residential Leasing Department<br />
                            852-2822-6800<br />
                          <span class="propertyblue"> <a href="mailto:[email protected]">[email protected]</a></SPAN></p>                          <p class="contenttextbold">&nbsp;</p>                          
                            </td>
                        </tr>
                    </table>
                    </ItemTemplate>
                    </asp:FormView>                keyword.Attributes.Add("onfocus", "this.value=''");
                DBFun db = new DBFun();
                string sql = "";
                if (!string.IsNullOrEmpty(Request.QueryString["b"]))
                {
                    sql = "select top 1 b.mgmt,a.building,a.add1 + ','+a.add2 as addr,b.rental,b.area,b.bedrooms,b.bathrooms,"
                        + "isnull(b.rem8,'')+isnull(b.rem9,'')+isnull(b.rem10,'')+isnull(b.rem11,'')+isnull(b.rem12,'')+isnull(b.rem13,'')+isnull(b.rem14,'')+isnull(b.rem15,'')+isnull(b.rem16,'')+isnull(b.rem17,'') as property_desc,"
                        + "isnull(a.rem1,'')+isnull(a.rem2,'')+isnull(a.rem3,'')+isnull(a.rem4,'')+isnull(a.rem5,'')+isnull(a.rem6,'')+isnull(a.rem7,'')+isnull(a.rem8,'')+isnull(a.rem9,'') as location_desc,"
                        + "case isnull(a.fac1,'') when '' then '' else '<br />&bull;&nbsp;'+a.fac1 end  as fac1, "
                        + "case isnull(a.fac2,'') when '' then '' else '<br />&bull;&nbsp;'+a.fac2 end  as fac2, "
                        + "case isnull(a.fac3,'') when '' then '' else '<br />&bull;&nbsp;'+a.fac3 end  as fac3 from building a,lease b where a.building=b.building and a.building='" + Request.QueryString["b"].Replace("'", "''") + "' and b.ref=" + Request.QueryString["r"];
                    DataSet ds = db.GetDataSetSql(sql);
                    FormView1.DataSource = ds;
                    FormView1.DataBind();
                    ds.Clear();                    //sql = "select a.sysid,b.photo_name,a.building,a.ref from lease a,lease_photo b where a.sysid=b.lease_sysid and a.building='" + Request.QueryString["b"].Replace("'", "''") + "'";
                    sql = " select a.sysid,a.building,a.ref,p_id from lease a,lease_photo b where a.sysid=b.lease_sysid   and a.building='" + Request.QueryString["b"].Replace("'", "''") + "' and a.ref=" + Request.QueryString["r"] + " union all select a.sysid,a.building,'0',p_id  from building a,building_photo b where a.sysid=b.building_sysid   and a.building='" + Request.QueryString["b"].Replace("'", "''") + "' order by ref";
                    TextBox1.Text = sql;
                    
                    DataTable dt1 = db.GetDataTable(sql);
                    FormView fv2 = (FormView)FormView1.FindControl("FormView2");                        fv2.DataSource = dt1;
                        fv2.DataBind();
             
                    dt1.Clear();
                    
                    
                    DataTable dt=db.GetDataTable(sql);
                    DataList datalist1=(DataList)FormView1.FindControl("DataList1");
                    if (datalist1 !=null)
                    {
                        datalist1.DataSource = dt;
                        datalist1.DataBind();
                    }
                    dt.Clear();

Answer 1

                keyword.Attributes.Add("onfocus", "this.value=''");
                DBFun db = new DBFun();
                string sql = "";
                if (!string.IsNullOrEmpty(Request.QueryString["b"]))
                {
                    sql = "select top 1 b.mgmt,a.building,a.add1 + ','+a.add2 as addr,b.rental,b.area,b.bedrooms,b.bathrooms,"
                        + "isnull(b.rem8,'')+isnull(b.rem9,'')+isnull(b.rem10,'')+isnull(b.rem11,'')+isnull(b.rem12,'')+isnull(b.rem13,'')+isnull(b.rem14,'')+isnull(b.rem15,'')+isnull(b.rem16,'')+isnull(b.rem17,'') as property_desc,"
                        + "isnull(a.rem1,'')+isnull(a.rem2,'')+isnull(a.rem3,'')+isnull(a.rem4,'')+isnull(a.rem5,'')+isnull(a.rem6,'')+isnull(a.rem7,'')+isnull(a.rem8,'')+isnull(a.rem9,'') as location_desc,"
                        + "case isnull(a.fac1,'') when '' then '' else '<br />&bull;&nbsp;'+a.fac1 end  as fac1, "
                        + "case isnull(a.fac2,'') when '' then '' else '<br />&bull;&nbsp;'+a.fac2 end  as fac2, "
                        + "case isnull(a.fac3,'') when '' then '' else '<br />&bull;&nbsp;'+a.fac3 end  as fac3 from building a,lease b where a.building=b.building and a.building='" + Request.QueryString["b"].Replace("'", "''") + "' and b.ref=" + Request.QueryString["r"];
                    DataSet ds = db.GetDataSetSql(sql);
                    FormView1.DataSource = ds;
                    FormView1.DataBind();
                    ds.Clear();                    //sql = "select a.sysid,b.photo_name,a.building,a.ref from lease a,lease_photo b where a.sysid=b.lease_sysid and a.building='" + Request.QueryString["b"].Replace("'", "''") + "'";
                    sql = " select a.sysid,a.building,a.ref,p_id from lease a,lease_photo b where a.sysid=b.lease_sysid   and a.building='" + Request.QueryString["b"].Replace("'", "''") + "' and a.ref=" + Request.QueryString["r"] + " union all select a.sysid,a.building,'0',p_id  from building a,building_photo b where a.sysid=b.building_sysid   and a.building='" + Request.QueryString["b"].Replace("'", "''") + "' order by ref";
                    TextBox1.Text = sql;
                    
                    DataTable dt1 = db.GetDataTable(sql);
                    FormView fv2 = (FormView)FormView1.FindControl("FormView2");                        fv2.DataSource = dt1;//这行出错.. 
                                             //System.NullReferenceException: 並未將物件參考設定為物件的執行個體                        fv2.DataBind();
             
                    dt1.Clear();
                    
                    
                    DataTable dt=db.GetDataTable(sql);
                    DataList datalist1=(DataList)FormView1.FindControl("DataList1");
                    if (datalist1 !=null)
                    {
                        datalist1.DataSource = dt;
                        datalist1.DataBind();
                    }
                    dt.Clear();
搞不明白怎么回事..请教了