HtmlValidationContext.ValidateImageValue Method

Removes unsafe or disallowed URLs and HTML markup and returns a validated imageValue parameter.

Namespace:  Microsoft.SharePoint.Publishing.Fields
Assembly:  Microsoft.SharePoint.Publishing (in Microsoft.SharePoint.Publishing.dll)

Syntax

'Declaration
Public Function ValidateImageValue ( _
    imageValue As ImageFieldValue, _
    <OutAttribute> ByRef tagsWereDropped As Boolean, _
    <OutAttribute> ByRef urlsWereDropped As Boolean _
) As ImageFieldValue
'Usage
Dim instance As HtmlValidationContext
Dim imageValue As ImageFieldValue
Dim tagsWereDropped As Boolean
Dim urlsWereDropped As Boolean
Dim returnValue As ImageFieldValue

returnValue = instance.ValidateImageValue(imageValue, _
    tagsWereDropped, urlsWereDropped)

public ImageFieldValue ValidateImageValue(
    ImageFieldValue imageValue,
    out bool tagsWereDropped,
    out bool urlsWereDropped
)

Parameters

• imageValue
  Type: Microsoft.SharePoint.Publishing.Fields.ImageFieldValue

  The ImageFieldValue object that is validated.

• tagsWereDropped
  Type: System.Boolean

  On return, this parameter is set to True if any disallowed tags were found and stripped during validation, otherwise False.

• urlsWereDropped
  Type: System.Boolean

  On return, this parameter is set to True if any disallowed URLs were found and stripped during validation, otherwise False.

Return Value

Type: Microsoft.SharePoint.Publishing.Fields.ImageFieldValue
The validated image value, from which all unsafe or disallowed content is removed.

Remarks

Removes any tags, attributes, or markup from an ImageFieldValue object that are unsafe or do not conform to the constraint settings that are applied to this HtmlValidationContext object.

The following properties do not affect this method: AllowFonts, AllowHeadings, AllowLists, AllowReusableContent, AllowTables, and AllowTextMarkup.

The AllowImages property is always forced to be set to True.

The AllowHyperlinks and RestrictUrlsToSiteCollection properties can be set to either True or False.

Examples

This sample constructs an HtmlValidationContext object and uses it to restrict and validate an ImageFieldValue object and return a report string. The sample functiontakes in two optional arguments:

• imageValue: An ImageFieldValue object to run through the validation. If this argument is empty then the application uses a default ImageFieldValue object instead.

• siteCollectionToRestrict: An SPSite to use for restricting the URLs in the HTML. If this argument is null then the URLs are not restricted to an SPSite.

// ValidateImageValueSample
using ImageFieldValue = Microsoft.SharePoint.Publishing.Fields.ImageFieldValue;
using LinkFieldValue = Microsoft.SharePoint.Publishing.Fields.LinkFieldValue;
using HtmlValidationContext = Microsoft.SharePoint.Publishing.Fields.HtmlValidationContext;
namespace Microsoft.SDK.SharePointServer.Samples
{

        public static string ValidateImageValueSample(
            ImageFieldValue imageValue,
            SPSite siteCollectionToRestrict)
        {
            ImageFieldValue imageValueToValidate = imageValue;
                    // If there is no provided value then construct a new default value
            if (null == imageValueToValidate)
            {
                imageValueToValidate = new ImageFieldValue();
                imageValueToValidate.ImageUrl = DefaultImageUrl;
                imageValueToValidate.Hyperlink = DefaultHyperlink;
            }
            string reportString = "Validating the following image value \n[" + imageValueToValidate.ToString() + "]";

            HtmlValidationContext validationContext = new HtmlValidationContext();

            // Set the constraint properties that apply for image values
            validationContext.AllowHyperlinks = true;

            if (null == siteCollectionToRestrict)
            {
                // No site collection provided so do not restrict URLs
                validationContext.RestrictUrlsToSiteCollection = false;
                validationContext.GuidOfThisSiteCollection = System.Guid.Empty;
            }
            else
            {
                // Restrict URLs to be from the provided site collection or to be server relative
                validationContext.RestrictUrlsToSiteCollection = true;
                validationContext.GuidOfThisSiteCollection = siteCollectionToRestrict.ID;
            }

            bool droppedTags;
            bool droppedUrls;
            ImageFieldValue validatedValue = 
                validationContext.ValidateImageValue(
                    imageValueToValidate,
                    out droppedTags,
                    out droppedUrls);

            reportString += "After validation we have the following image value \n[" + validatedValue.ToString() + "]";

            return reportString;
        }

See Also

Reference

HtmlValidationContext Class

HtmlValidationContext Members

Microsoft.SharePoint.Publishing.Fields Namespace