C# 如何将图像 url 转换为 system.drawing.image
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How can I convert image url to system.drawing.image
提问by Mina Gabriel
I'm using VB.NetI have an url of an image, let's say http://localhost/image.gif
我正在使用VB.Net我有一个图片的网址，让我们说http://localhost/image.gif
I need to create a System.Drawing.Image object from that file.
我需要从该文件创建一个 System.Drawing.Image 对象。
Noticesave this to a file and then open it is not one of my options
also i'm using ItextSharp
请注意将其保存到文件然后打开它不是我的选项之一，我也在使用ItextSharp
here is my code :
这是我的代码：
Dim rect As iTextSharp.text.Rectangle
rect = iTextSharp.text.PageSize.LETTER
Dim x As PDFDocument = New PDFDocument("chart", rect, 1, 1, 1, 1)
x.UserName = objCurrentUser.FullName
x.WritePageHeader(1)
For i = 0 To chartObj.Count - 1
Dim chartLink as string = "http://localhost/image.gif"
x.writechart( ** it only accept system.darwing.image ** )
Next
x.WritePageFooter()
x.Finish(False)
采纳答案by Varius
You could use WebClient class to download image and then MemoryStream to read it:
您可以使用 WebClient 类下载图像，然后使用 MemoryStream 来读取它：
C#
C＃
WebClient wc = new WebClient();
byte[] bytes = wc.DownloadData("http://localhost/image.gif");
MemoryStream ms = new MemoryStream(bytes);
System.Drawing.Image img = System.Drawing.Image.FromStream(ms);
VB
VB
Dim wc As New WebClient()
Dim bytes As Byte() = wc.DownloadData("http://localhost/image.gif")
Dim ms As New MemoryStream(bytes)
Dim img As System.Drawing.Image = System.Drawing.Image.FromStream(ms)
回答by Guilherme de Jesus Santos
You can try this to get the Image
你可以试试这个来获取图像
Dim req As System.Net.WebRequest = System.Net.WebRequest.Create("[URL here]")
Dim response As System.Net.WebResponse = req.GetResponse()
Dim stream As Stream = response.GetResponseStream()
Dim img As System.Drawing.Image = System.Drawing.Image.FromStream(stream)
stream.Close()
回答by blang32
Dim c As New System.Net.WebClient
Dim FileName As String = "c:\StackOverflow.png"
c.DownloadFile(New System.Uri("http://cdn.sstatic.net/stackoverflow/img/sprites.png?v=5"), FileName)
Dim img As System.Drawing.Image
img = System.Drawing.Image.FromFile(FileName)
回答by VahidN
iTextSharp is able to accept Uri's:
iTextSharp 能够接受 Uri 的：
Image.GetInstance(uri)
回答by T_D
The other answers are also correct, but it hurts to see the Webclient and MemoryStream not getting disposed, I recommend putting your code in a using.
其他答案也是正确的，但是看到 Webclient 和 MemoryStream 没有被处理会很痛苦，我建议将您的代码放在using.
Example code:
示例代码：
using (var wc = new WebClient())
{
using (var imgStream = new MemoryStream(wc.DownloadData(imgUrl)))
{
using (var objImage = Image.FromStream(imgStream))
{
//do stuff with the image
}
}
}
The required imports at top of your file are System.IO, System.Net& System.Drawing
文件顶部所需的导入是System.IO, System.Net&System.Drawing
In VB.net the syntax was using wc as WebClient = new WebClient() {etc
在 VB.net 中，语法是using wc as WebClient = new WebClient() {等
回答by Filix Mogilevsky
You can use HttpClient and accomplish this task async with few lines of code.
您可以使用 HttpClient 并通过几行代码异步完成此任务。
public async Task<Bitmap> GetImageFromUrl(string url)
{
var httpClient = new HttpClient();
var stream = await httpClient.GetStreamAsync(url);
return new Bitmap(stream);
}
