blogs.conchango.com

Just spent the day trying to do this, having not really written sharepoint code before. Seeing as it took most of the day to figure out, and perfect, I thought I would post the solution in case I ever needed to repeat this again...

In the customised UploadAtlasDocument.aspx in the 12 hive C:\Program Files\Common Files\Microsoft Shared\web server extensions\12\TEMPLATE\LAYOUTS\ I added the following code...

<script runat="server">

 

    /// <summary>

    /// Validates the posted filename doesn't already exist in the sharepoint list CH Documents

    /// </summary>

    /// <param name="source"></param>

    /// <param name="args"></param>

    void custVldFileExists_ServerValidate(object source, System.Web.UI.WebControls.ServerValidateEventArgs args)

    {

        //note you don't get intellisense for this.OverwriteSingle

        //as it is nested in a template control

        if (!string.IsNullOrEmpty(args.Value)

            && this.OverwriteSingle.Visible == true

            && this.OverwriteSingle.Checked == false)

        {

            FileInfo fileInfo = new FileInfo(this.InputFile.PostedFile.FileName);

 

            string newFileName = fileInfo.Name;

 

            using (SPSite site = new SPSite(SPContext.Current.Web.Url))

            {

                using (SPWeb webSite = site.OpenWeb())

                {

                    SPList chDocumentsList = webSite.Lists["CH Documents"];

                   

                    //do we have any files existing in the list already

                    if (chDocumentsList != null && chDocumentsList.RootFolder.Files.Count > 0)

                    {

                        //we have files in the list already

                        //so iterate round each one and see if the one we're about to upload

                        //already exists in the list.

                        foreach (SPFile spFile in chDocumentsList.RootFolder.Files)

                        {

                            if (string.Compare(spFile.Name, newFileName, StringComparison.InvariantCultureIgnoreCase) == 0)

                            {

                                //the file name we're uploading

                                //matches an existing file,

                                //and the user hasn't checked the OverwriteMultiple check box

                                //so invalidate this validator

                                //in order to get message back to the user.

                                args.IsValid = false;

                                break;

                            }

                        }

                    }

                   

                    webSite.Close();

                }

                site.Close();

            }

        }

    }

</script>

...

<TR><TD>

            <wssawc:InputFormRequiredFieldValidator ID="InputFormRequiredFieldValidator1" ControlToValidate="InputFile"

               Display="Dynamic" ErrorMessage="Please click the browse button to upload a file." Runat="server"

               BreakBefore="false" BreakAfter="false" EnableClientScript="false" />

            <asp:CustomValidator ID="custVldFileExists" runat="server"

                    ErrorMessage="File already exists. Please either rename the file or select overwrite to replace the existing file."

                    ControlToValidate="InputFile" OnServerValidate="custVldFileExists_ServerValidate"

                    Display="Static" EnableClientScript="false" ></asp:CustomValidator>

            <asp:CustomValidator ID="CustomValidator1" ControlToValidate="InputFile"

               Display = "Dynamic"

               ErrorMessage = "<%$Resources:wss,upload_document_file_invalid%>"

               OnServerValidate="ValidateFile"

               runat="server" EnableClientScript="false" />

                              </TD></TR>

Note the EnableClientScript="false" was required so that the error would get cleared from our custom validator if the user deleted the text out of the input file control, and then hit OK again.