如何调整和上传仅适用于 .jpg 扩展名的图像：
在upload.aspx 页面中
<asp:FileUpload ID="ProductImage" runat="server"/>
<asp:Button ID="Button1" runat="server" OnClick="Button1_Click" Text="Upload" />
<asp:TextBox runat="server" ID="txtProductName" CssClass="form-control" />
<asp:RequiredFieldValidator runat="server" ControlToValidate="txtProductName" ErrorMessage="The Product name field is required." />
并上传.aspx.cs
调整大小
/// <summary>
/// Created By Rajib Chowdhury Mob. 01766-306306; Web: http://onlineshoping.somee.com/
/// Complete This Page Coding On January 05, 2014
/// Programing C# By Visual Studio 2013 For Web
/// Dot Net Version 4.5
/// Database Virsion MSSQL Server 2005
/// </summary>
public bool ResizeImageAndUpload(System.IO.FileStream newFile, string folderPathAndFilenameNoExtension, double maxHeight, double maxWidth)
{
try
{
// Declare variable for the conversion
float ratio;
// Create variable to hold the image
System.Drawing.Image thisImage = System.Drawing.Image.FromStream(newFile);
// Get height and width of current image
int width = (int)thisImage.Width;
int height = (int)thisImage.Height;
// Ratio and conversion for new size
if (width > maxWidth)
{
ratio = (float)width / (float)maxWidth;
width = (int)(width / ratio);
height = (int)(height / ratio);
}
// Ratio and conversion for new size
if (height > maxHeight)
{
ratio = (float)height / (float)maxHeight;
height = (int)(height / ratio);
width = (int)(width / ratio);
}
// Create "blank" image for drawing new image
Bitmap outImage = new Bitmap(width, height);
Graphics outGraphics = Graphics.FromImage(outImage);
SolidBrush sb = new SolidBrush(System.Drawing.Color.White);
// Fill "blank" with new sized image
outGraphics.FillRectangle(sb, 0, 0, outImage.Width, outImage.Height);
outGraphics.DrawImage(thisImage, 0, 0, outImage.Width, outImage.Height);
sb.Dispose();
outGraphics.Dispose();
thisImage.Dispose();
// Save new image as jpg
outImage.Save(Server.MapPath(folderPathAndFilenameNoExtension + ".jpg"), System.Drawing.Imaging.ImageFormat.Jpeg);
outImage.Dispose();
return true;
}
catch (Exception)
{
return false;
}
}
还有 Button1_Click 事件
string filePath = "~\\Image\\";//your normal image path
if (Page.IsValid)
{
HttpPostedFile myFile = ProductImage.PostedFile;//Get Slected Image
int nFileLen = myFile.ContentLength;//Get slected Image Size
string myimag = txtProductName.Text;//Get user input image name
Guid ImageName = Guid.NewGuid();//get unique id
if ((myFile != null) && (nFileLen > 1048576))
{
LabelAddStatus.Text = "minimum size exceed"; //If file image size 1 MB above
}
else
{
try
{
if (ProductImage.HasFile)
{
String fileExtension = System.IO.Path.GetExtension(ProductImage.FileName).ToLower();
String[] allowedExtensions = { ".jpg" };//Declare For Allowed Extension
for (int i = 0; i < allowedExtensions.Length; i++)
{
if (fileExtension == allowedExtensions[i])
{
// Read file into a data stream
byte[] myData = new Byte[nFileLen];
myFile.InputStream.Read(myData, 0, nFileLen);
myFile.InputStream.Dispose();
// Save the stream to disk as temporary file. make sure the path is unique!
System.IO.FileStream newFile
= new System.IO.FileStream(Server.MapPath(filePath + "_temp.jpg"),
System.IO.FileMode.Create);
newFile.Write(myData, 0, myData.Length);
bool success = ResizeImageAndUpload(newFile, filePath + ("thumbs"+myimag + ImageName), 100, 100);//Save image your thumb image path
success = ResizeImageAndUpload(newFile, filePath + (myimag + ImageName), 768, 1024);//Save image your normal image path
//delete the temp file.
newFile.Close();
System.IO.File.Delete(Server.MapPath(filePath + "_temp.jpg"));
LabelAddStatus.Text = "File uploaded.";
}
else
{
LabelAddStatus.Text = "Unable to accept file type..";
}
}
}
}
catch (Exception)
{
//No Exception Message
}
}
}
谢谢...