這個問題的各種口味已被問到，但我還沒有找到正確的答案。ASP.NET：獲取圖像的高度和寬度
假設我在文件服務器上有一個.jpg圖像，並且需要獲取它的高度和寬度。我如何在asp.net中做到這一點？
我見過這表明做一些像這樣的幾個答案：
System.Drawing.Image image=System.Drawing.Image.FromFile(PicturePath);
int ActualWidth=image.Width;
int ActualHeight=image.Height;
image.Dispose();
這會工作得很好，除了classes within the System.Drawing namespace are not supported for use within an ASP.NET service。
那麼，你如何得到在ASP.net中圖像的實際高度和寬度？
在ASPX
<asp:image ID="img1" runat="server" src="" />
和代碼添加一個服務器側圖像控制背後給它一個src
img1.src = System.Drawing.Image.FromFile(PicturePath);
int ActualWidth = img1.Width;
int ActualHeight = img1.Height;
img1.src = "";
爲了避免使用System.Drawing命名空間：
對於GIF，高度和寬度是文件頭中的4個字節的整數。 （地址0×12的寬度，0x16爲高）
爲JPG格式，你可以嘗試寫一個函數喜歡在這裏找到了一個：http://www.64lines.com/jpeg-width-height 它通過在JPG作爲數據的數組，它得到的高度和寬度。
謝謝，但你的鏈接不起作用。 – Anthony 2010-01-09 12:21:06
抱歉Anothony，修正了它。 – 2010-01-11 01:59:56
願這幫助
string lPath = Server.MapPath("~\\Images1\\") + dsProd.Tables[0].Rows[i]["Image1"].ToString();
Image1.ImageUrl = "Images1\\" + dsProd.Tables[0].Rows[i]["Image1"].ToString();
Image2.ImageUrl = "Images1\\" + dsProd.Tables[0].Rows[i]["Image2"].ToString();
string currentImagePath = lPath.ToString();// Session["FullImagePath"] + "\\" + GetCurrentFileName();
Bitmap bmp = new Bitmap(currentImagePath);
int iActualWidth=0,iActualHeight=0;
for (int j = 1; j <= 100; j++)
{
if ((bmp.Width/j) > 150)
{
iActualWidth = bmp.Width/j;
iActualHeight = bmp.Height/j;
}
else
{
break;
}
}
Image1.Height = new Unit(iActualHeight);
Image1.Width = new Unit(iActualWidth);
進口System.Drawing.Image對象，System.IO
Dim image As System.Drawing.Image
image = image.FromFile([filepath])
If image.Width > 440 Or image.Height > 440 Then
'show resized
else
'leave as is
end if
問題中的代碼有什麼區別？ – Anthony 2011-10-06 18:49:42
我已經轉換C++代碼，C＃以供將來參考：
static bool get_jpeg_size(byte[] data, int data_size, ref int width, ref int height)
{
//Check for valid JPEG image
int i = 0; // Keeps track of the position within the file
if (data[i] == 0xFF && data[i + 1] == 0xD8 && data[i + 2] == 0xFF && data[i + 3] == 0xE0)
{
i += 4;
// Check for valid JPEG header (null terminated JFIF)
if (data[i + 2] == 'J' && data[i + 3] == 'F' && data[i + 4] == 'I' && data[i + 5] == 'F' && data[i + 6] == 0x00)
{
//Retrieve the block length of the first block since the first block will not contain the size of file
var block_length = data[i] * 256 + data[i + 1];
while (i < data_size)
{
i += block_length; //Increase the file index to get to the next block
if (i >= data_size) return false; //Check to protect against segmentation faults
if (data[i] != 0xFF) return false; //Check that we are truly at the start of another block
if (data[i + 1] == 0xC0)
{ //0xFFC0 is the "Start of frame" marker which contains the file size
//The structure of the 0xFFC0 block is quite simple [0xFFC0][ushort length][uchar precision][ushort x][ushort y]
height = data[i + 5] * 256 + data[i + 6];
width = data[i + 7] * 256 + data[i + 8];
return true;
}
else
{
i += 2; //Skip the block marker
block_length = data[i] * 256 + data[i + 1]; //Go to the next block
}
}
return false; //If this point is reached then no size was found
}
else { return false; } //Not a valid JFIF string
}
else { return false; } //Not a valid SOI header
}
用法：
using (var stream = File.OpenRead(path))
{
using (var m = new MemoryStream())
{
stream.CopyTo(m);
var arr = m.ToArray();
int w = 0, h = 0;
get_jpeg_size(arr, arr.Length, ref w, ref h);
Console.WriteLine(w + "x" + h);
}
}
Imports System.IO
Imports System.Drawing
Dim sFile As Stream = fuPhoto2.PostedFile.InputStream
Dim img As System.Drawing.Image = System.Drawing.Image.FromStream(sFile)
If img.PhysicalDimension.Width > 700 And img.PhysicalDimension.Height > 300 Then
strPhotoName = fuPhoto2.FileName
fuPhoto2.SaveAs(Server.MapPath("~/Images/") +
fuPhoto2.FileName)
Else
lblErrMeg2.Text = "Image size must be greater than 700 X 300!"
fuPhoto2.Focus()
Exit Sub
End If
根據問題中提到的MSDN頁面，不應在ASP.net中使用System.Drawing。你的「img」變量是基於它的。此外，img.PhysicalDimension.Width和img.Width（在問題中使用）之間的區別是什麼？ – Anthony 2012-09-06 14:33:06
您可以使用「位圖」類。
C＃
Bitmap bitmap = new Bitmap(filepath);
int iWidth = bitmap.Width;
int iHeight = bitmap.Height;
VB
Dim bitmap As New Bitmap(filepath)
Dim iWidth As Integer = bitmap.Width
Dim iHeight As Integer = bitmap.Height
進口iTextSharp.text
剛剛創建PFD時使用的工具。
Dim URel As String
URel = "https://......."
Dim pic As iTextSharp.text.Image
pic = iTextSharp.text.Image.GetInstance(URel)
Dim sizee As String
sizee = pic.Height
SOURR = "<img src='" & URel & "' alt='' />"
我有我的圖片在ListView作爲ImageButton的，我需要他們的寬度和高度，所以我在這裏找到了解決方案： http://forums.asp.net/t/1262878.aspx?how+to+get+the+image+width+and+height+argh
和我的工作代碼：
ListViewItem item = e.Item;
ImageButton img = item.FindControl("img") as ImageButton;
FileStream fs = new FileStream(MapPath(img.ImageUrl) , FileMode.Open, FileAccess.Read, FileShare.Read);
System.Drawing.Image dimg = System.Drawing.Image.FromStream(fs);
int width = Convert.ToInt32(dimg.Width);
int height = Convert.ToInt32(dimg.Height);
我希望它可以幫助你
相關，但一個不同的問題：http://stackoverflow.com/questions/390532/system-drawing-in-windows-or-asp-net-services – jball 2010-01-06 21:12:30
Image.FromStream（stream，false）將加載寬度和高度，而不分析所有圖像數據。確保你放棄圖片後面的流，你會沒事的。這個警告是因爲一般的程序員懶得無法正確處理手動內存管理。 – 2011-07-30 07:05:45