我正在使用 C# 开发专辑查看器。作为应用程序的一部分，我需要将所选文件夹的所有图像显示为缩略图。我不知道如何创建缩略图。
完成该功能的任何代码、链接或建议都会非常有帮助。谢谢。
【问题讨论】：
标签： c# image thumbnails
public System.Drawing.Image GetThumbnailImage(int thumbWidth, int thumbHeight, System.Drawing.Image.GetThumbnailImageAbort callback, System.IntPtr callbackData)
Member of System.Drawing.Image
Summary:
Returns a thumbnail for this System.Drawing.Image.
Parameters:
thumbWidth: The width, in pixels, of the requested thumbnail image.
thumbHeight: The height, in pixels, of the requested thumbnail image.
callback: A System.Drawing.Image.GetThumbnailImageAbort delegate. In GDI+ version 1.0, the delegate is not used. Even so, you must create a delegate and pass a reference to that delegate in this parameter.
callbackData: Must be System.IntPtr.Zero.
Returns:
An System.Drawing.Image that represents the thumbnail.
【讨论】：
检查this article。它可能会对您有所帮助... 代码从文本框中提供的图像创建一个 Image 对象。然后使用 Image.GetThumbnailImage()，代码创建一个大小为 100*100 的缩略图。
【讨论】：
[HttpPost]
public PartialViewResult DisplayGalleryThumbs(string galleryId)
{
int pageNumber = Convert.ToInt32(galleryId.Split('_')[2]);
Guid feedId = new Guid(galleryId.Split('_')[1]);
var images = _feedDomain.ShowPostById(feedId.ToString()).Images;
int totalNumberOfPages = CountNumberOfPages(images);
string action = galleryId.Split('_')[3];
var dict = new Dictionary<int, List<FeedImage>>();
var pagedImages = new List<FeedImage>();
int i = 1;
int a = 1;
foreach (FeedImage image in images)
{
pagedImages.Add(image);
if (i % NumberOfImagesPerPage == 0)
{
dict.Add(a, pagedImages);
a++;
pagedImages=new List<FeedImage>();
}
if (i >= images.Count()) dict.Add(a, pagedImages);
i++;
}
if (action=="next")
{
pageNumber += 1;
}
else
{
pageNumber -= 1;
}
var galleryModel = new FeedThumbGalleryModel
{
Images = dict.FirstOrDefault(c => c.Key == pageNumber).Value,
FeedId = feedId,
PageNumber = pageNumber,
NumberOfPages = totalNumberOfPages,
NumberOfImagesPerPage = NumberOfImagesPerPage,
TotalNumberOfImages = images.Count()
};
return PartialView("~/Views/Feed/_DisplayGalleryThumbs.cshtml", galleryModel);
}
@helper Render(FeedThumbGalleryModel model)
{
if (model.Images != null)
{
string linkNext = "linkNext_" + model.FeedId + "_" + model.PageNumber + "_next";
string linkPrev = "linkPrev_" + model.FeedId + "_" + model.PageNumber + "_prev";
string thumbFeedId = "feedThumbDiv_" + model.FeedId;
<div id="@thumbFeedId">
<table>
<tr>
<td style="width: 30px;vertical-align: top;">
@if (model.NumberOfPages > 1)
{
if (model.PageNumber <= model.NumberOfPages && model.PageNumber > 1 || model.PageNumber == model.NumberOfPages)
{
<a class="page-action" href="#" id="@linkPrev">Prev</a>
}
}
</td>
<td style="width: 120px;vertical-align: top">
@if (model.NumberOfPages>1)
{
for (int a = 1; a <= model.NumberOfPages; a++)
{
int currentPage = a - 1;
string pageLink = "linkNext_" + model.FeedId + "_" + currentPage + "_next";
string classname = a==model.PageNumber ? "page-number-list" : "page-number-list1";
<a href="#" id="@pageLink" class="@classname">@a</a>
}
}
</td>
<td style="width: 220px;vertical-align: top;">
@if (model.PageNumber < model.NumberOfPages)
{
<a class="page-action" href="#" id="@linkNext">Next</a>
}
</td>
<td style="width: 150px;vertical-align: top;">
@{var thisId = "SeeAll_" + model.FeedId;}
@if (model.TotalNumberOfImages > 12)
{
<a id="@thisId" class="view-all">View All</a>
}
</td>
<td style="vertical-align: top">
<div class="number-of-images">
@model.TotalNumberOfImages images
</div>
</td>
</tr>
<tr>
<td colspan="5">
<div style="width: 660px;padding-top: 10px">
@{int i = 1;}
@foreach (FeedImage m in model.Images)
{
string thumbThumb = ConfigurationManager.AppSettings["DisplayThumbPath"] + m.ImageId;
string imageUrl = "/feed/DisplayImage/" + model.FeedId + "_" + m.ImageId;
<div class="thumbnail image">
<a class='show-image' href="@imageUrl">
<img border="0" class="image" src="@thumbThumb" width="125" height="125" alt="" />
</a>
</div>
if (i % model.NumberOfImagesPerPage == 0)
{
break;
}
i++;
}
<br/>
</div>
</td>
</tr>
</table>
</div>
}
}
public class FeedImage
{
public Guid ImageId { get; set; }
public string ImageUrl { get; set; }
public string ImageName { get; set; }
public double ImageSize { get; set; }
public string FileExtension { get; set; }
public string ImageType { get; set; }
public FeedPost Post { get; set; }
public List<FeedLike> Likes { get; set; }
public List<FeedComment> Comments { get; set; }
public DateTime DateCreated { get; set; }
public string DateCreatedIso8601 { get; set; }
}
private int CountNumberOfPages(List<FeedImage> images)
{
if (images == null) return 0;
return (images.Count() + NumberOfImagesPerPage - 1) / NumberOfImagesPerPage;
}
$("[class='page-action']").live('click', function () {
var feedArr = $(this).attr('id').split('_');
var thisDivId = '#feedThumbDiv_' + feedArr[1];
$.post('/Feed/DisplayGalleryThumbs', { galleryId: $(this).attr('id') },
function (html) {
$(thisDivId).replaceWith(html);
});
return false;
});
这是一个使用 MVC3 进行缩略图分页预览的 ajax 解决方案。我将其用于我的新闻提要以通过图片库列出。不要介意在视图中大量使用表格，我的 UI 有点受限。
【讨论】：
我向你推荐我过去使用的一种方式：使用 ListView 并动态加载关联的 ImageList 中的图像。您可以使用 rdkleine 提出的策略以缩略图形式加载图像。您必须遵循的重要原则是不要加载所有图像，如果用户真的看不到它们。使用列表视图，您可以通过设置 VirtualMode = true 来实现此目的，并且仅在实际显示时才提供图像。
【讨论】：