I've developed a custom catalog zone class, which I declare on my web page like this:

<drp:ReportCatalogZone ID="wpczCatalog" runat="server" BackColor="#FFFBD6" BorderColor="#CCCCCC" BorderWidth="1px" Font-Names="Verdana" Padding="6">

[... some content here ...]

</drp:ReportCatalogZone>

Now when I'm trying to open my page in design view, I'm getting this error message written inside of the control:

Error rendering control - wpczCatalog
An unhandled exception has occured.
Object reference is not set to an instance of an object.

Can anyone please help with that?

Andrey.

You're probably forgetting to initialize some child control of the custom webpartzone. Could you post some of the code of your custom webpartzone? (isn't it a catalogzone by the way as the name seems to indicate?) There doesn't seem to be an error in the code snippet you posted.

Rob82:

You're probably forgetting to initialize some child control of the custom webpartzone. Could you post some of the code of your custom webpartzone? (isn't it a catalogzone by the way as the name seems to indicate?) There doesn't seem to be an error in the code snippet you posted.

You're right! It is CatalogZone rather than WebPartZone. Sorry about that.

Here's the source code:

public class ReportCatalogZone : CatalogZone

public ReportCatalogZone() {}

protected override CatalogPartCollection CreateCatalogParts() {

And here is declarative part (complete):

<drp:ReportCatalogZone ID="wpczCatalog" runat="server" BackColor="#FFFBD6" BorderColor="#CCCCCC" BorderWidth="1px" Font-Names="Verdana" Padding="6">

<HeaderVerbStyle Font-Bold="False" Font-Size="0.8em" Font-Underline="False" ForeColor="#333333" />
<PartTitleStyle BackColor="#990000" Font-Bold="True" Font-Size="0.8em" ForeColor="White" />
<PartChromeStyle BorderColor="#FFCC66" BorderStyle="Solid" BorderWidth="1px" />
<InstructionTextStyle Font-Size="0.8em" ForeColor="#333333" />
<PartLinkStyle Font-Size="0.8em" />
<EmptyZoneTextStyle Font-Size="0.8em" ForeColor="#333333" />
<LabelStyle Font-Size="0.8em" ForeColor="#333333" />
<VerbStyle Font-Names="Verdana" Font-Size="0.8em" ForeColor="#333333" />

<ZoneTemplate>

<asp:PageCatalogPart ID="wpcPageCatalog" runat="server" />
<drp:ReportCatalogPart runat="server" ID="ReportCatalogPart1" ReportConfigurationFile="~/ReportConfig.xml" SQLConfigurationFile="~/SQLConfig.xml" Title="Registered Reports" />

</ZoneTemplate>

<PartStyle BorderColor="#FFFBD6" BorderWidth="5px" />
<SelectedPartLinkStyle Font-Size="0.8em" />
<FooterStyle BackColor="#FFCC66" HorizontalAlign="Right" />
<HeaderStyle BackColor="#FFCC66" Font-Bold="True" Font-Size="0.8em" ForeColor="#333333" />
<EditUIStyle Font-Names="Verdana" Font-Size="0.8em" ForeColor="#333333" />

</drp:ReportCatalogZone>

Thanks,

Andrey.

I see that you've got a  method called AddReportCatalogPart, but it seems like it is never used. This means that your _malCatalogParts collection will just be empty and that probably causes return new CatalogPartCollection(base.CreateCatalogParts(), _malCatalogParts) to throw an error. I think that since you already declaratively added a ReportCatalogPart there is no need to override CreateCatalogParts(). Try removing that method from your custom catalogzone and it should run just fine.

I removed everything from the ReportCatalogZone class, now it looks like this:

public class ReportCatalogZone : CatalogZone

}

And still there's this error in the designer. Everything work just fine at the run-time.

Andrey.

I just decided to remove <drp:ReportCatalogZone>, and revert back to <asp:CatalogZone>. Everything worked, but still there's an error in the designer. I think it's related to the CatalogPart object rather than CatalogZone object.

Should I post the code for the class derived from CatalogPart? There's slightly more code in it...

Thanks,

Andrey.

Go ahead, it might indeed be some control that you try to render in the reportCatalogPart without initializing. 

Ok, this is the code for ReportCatalogPart class:

public class ReportCatalogPart : CatalogPart
    {

        private ReportConfigurationReader _mrptReader;
        private SQLConfigurationReader _msqlReader;

        private string _mstrReportConfigurationFile;
        private string _mstrSQLConfigurationFile;

        public ReportCatalogPart()
        {
            if (ViewState["ReportConfigurationFile"] != null) _mstrReportConfigurationFile = (string)ViewState["ReportConfigurationFile"];
            if (ViewState["SQLConfigurationFile"] != null) _mstrSQLConfigurationFile = (string)ViewState["SQLConfigurationFile"];
            CreateConfiguration();
        }

        [
        UrlProperty(),
        DefaultValue(""),
        Editor(typeof(System.Web.UI.Design.XmlUrlEditor), typeof(System.Drawing.Design.UITypeEditor)),
        ]
        public string ReportConfigurationFile
        {
            get
            {
                return _mstrReportConfigurationFile;
            }
            set
            {
                _mstrReportConfigurationFile = value;
                ViewState["ReportConfigurationFile"] = value;
            }
        }

        [
        UrlProperty(),
        DefaultValue(""),
        Editor(typeof(System.Web.UI.Design.XmlUrlEditor), typeof(System.Drawing.Design.UITypeEditor)),
        ]
        public string SQLConfigurationFile
        {
            get
            {
                return _mstrSQLConfigurationFile;
            }
            set
            {
                _mstrSQLConfigurationFile = value;
                ViewState["SQLConfigurationFile"] = value;
            }
        }

        public override WebPartDescriptionCollection GetAvailableWebPartDescriptions()
        {
            CreateConfiguration();
            if (_mrptReader != null)
            {
                return ReportLoader.GetReportDescriptions(_mrptReader);
            }
            return null;
        }

        public override WebPart GetWebPart(WebPartDescription description)
        {
            CreateConfiguration();
            if (_msqlReader != null)
            {
                return ReportLoader.GetReportWebPart(this.Page, _mrptReader, _msqlReader, description.ID);
            }
            return null;
        }

        private void CreateConfiguration()
        {
            if (_mrptReader == null && _mstrReportConfigurationFile != "" && _mstrReportConfigurationFile != null) _mrptReader = new ReportConfigurationReader(this.Context.Server.MapPath(_mstrReportConfigurationFile));
            if (_msqlReader == null && _mstrSQLConfigurationFile != "" && _mstrSQLConfigurationFile != null) _msqlReader = new SQLConfigurationReader(this.Context.Server.MapPath(_mstrSQLConfigurationFile));
        }
    }

 Thanks,

Andrey.

Ok, I got it working... It looks like two configuration editors were referred, and no instance of those were created... I changed two methods:

public override WebPartDescriptionCollection GetAvailableWebPartDescriptions()
        {
            if (!DesignMode)
            {
                CreateConfiguration();
                if (_mrptReader != null)
                {
                    return ReportLoader.GetReportDescriptions(_mrptReader);
                }
            }
            return new WebPartDescriptionCollection();
        }

        public override WebPart GetWebPart(WebPartDescription description)
        {
            if (!DesignMode)
            {
                CreateConfiguration();
                if (_msqlReader != null)
                {
                    return ReportLoader.GetReportWebPart(this.Page, _mrptReader, _msqlReader, description.ID);
                }
            }
            return null;
        }

And now it's working.

Thanks anyway for your help!

Andrey.