當網頁ViewState過大時，系統會需要使用壓縮技術減少USER下載網頁的時間，因此我參考了gipi與Mr.NFrankenstein的文章，改寫出Update Panel下ViewState過大進行壓縮的程式。
當網頁ViewState過大時，系統會需要使用壓縮技術減少USER下載網頁的時間，因此我參考了gipi與Mr.NFrankenstein的文章，改寫出Update Panel下ViewState過大進行壓縮的程式。
///
/// 設定序列化後的字串長度為多少後啟用壓縮
///
private static int LimitLength = 10240;
///
/// 設定壓縮比率，壓縮比率越高性消耗也將增大
///
private static int ZipLevel = ICSharpCode.SharpZipLib.Zip.Compression.Deflater.BEST_COMPRESSION;
///
/// override掉Page中原來的SavePageStateToPersistenceMedium()
///
protected override void SavePageStateToPersistenceMedium(object state)
{
Pair pair = default(Pair);
PageStatePersister persister = this.PageStatePersister;
object ViewState = null;
LosFormatter formatter = new LosFormatter();
StringWriter writer = new StringWriter();
byte[] compressedData = null;
string viewStateStr = string.Empty;
if (state is Pair)
{
pair = (Pair)state;
persister.ControlState = pair.First;
ViewState = pair.Second;
}
else
ViewState = state;
formatter.Serialize(writer, ViewState);
viewStateStr = writer.ToString();
//沒超過壓縮標準則不壓縮
if (viewStateStr.Length < LimitLength)
ZipLevel = ICSharpCode.SharpZipLib.Zip.Compression.Deflater.NO_COMPRESSION;
compressedData = this.CompressStrToByte(viewStateStr, ZipLevel);
viewStateStr = Convert.ToBase64String(compressedData);
persister.ViewState = viewStateStr;
persister.Save();
}
///
/// 重寫將所有保存的視圖狀態資訊載入到頁面物件
///
/// 保存的ViewState
protected override object LoadPageStateFromPersistenceMedium()
{
string viewState = string.Empty;
PageStatePersister persister = this.PageStatePersister;
byte[] uncompressedData = null;
LosFormatter formatter = new LosFormatter();
persister.Load();
viewState = persister.ViewState.ToString();
uncompressedData = this.DeCompressStrToByte(viewState);
viewState = Convert.ToBase64String(uncompressedData);
return new Pair(persister.ControlState, formatter.Deserialize(viewState));
}
///
/// 對字串進行壓縮
///
///字串
/// 返回流的位元組陣列
public static Byte[] CompressStrToByte(string CompressString, int ZipLevel = Deflater.DEFAULT_COMPRESSION)
{
//將字串轉換為位元組陣列
Byte[] pBytes = System.Convert.FromBase64String(CompressString);
//建立記憶體的Stream
MemoryStream mMemory = new MemoryStream();
Deflater mDeflater = new Deflater(ZipLevel);
ICSharpCode.SharpZipLib.Zip.Compression.Streams.DeflaterOutputStream mStream =
new ICSharpCode.SharpZipLib.Zip.Compression.Streams.DeflaterOutputStream(mMemory, mDeflater, 131072);
mStream.Write(pBytes, 0, pBytes.Length);
mStream.Close();
return mMemory.ToArray();
}
///
/// 解壓縮字串
///
///壓縮字串
/// 返回流的位元組陣列
public static Byte[] DeCompressStrToByte(string CompressString)
{
//將Base64字串轉換為位元組陣列
Byte[] pBytes = System.Convert.FromBase64String(CompressString);
ICSharpCode.SharpZipLib.Zip.Compression.Streams.InflaterInputStream mStream =
new ICSharpCode.SharpZipLib.Zip.Compression.Streams.InflaterInputStream(new MemoryStream(pBytes));
//創建支援記憶體存儲的流
MemoryStream mMemory = new MemoryStream();
Int32 mSize;
Byte[] mWriteData = new Byte[4096];
while (true)
{
mSize = mStream.Read(mWriteData, 0, mWriteData.Length);
if (mSize > 0)
{
mMemory.Write(mWriteData, 0, mSize);
}
else
{
break;
}
}
mStream.Close();
return mMemory.ToArray();
}
