linQ異常的改善: 將 varchar 資料類型轉換成 datetime 資料類型時，產生超出範圍的值

會出現此問題主因是null值所致的問題，改善方法是將日期型態的資料增加null值的處理即可改善此問題。

Fix error: A possible object cycle was detected. This can either be due to a cycle or if the object depth is larger than the maximum allowed depth of 32. Consider using ReferenceHandler.Preserve on JsonSerializerOptions to support cycles.

In order to fix the error:

System.Text.Json.JsonException: A possible object cycle was detected. This can either be due to a cycle or if the object depth is larger than the maximum allowed depth of 32. Consider using ReferenceHandler.Preserve on JsonSerializerOptions to support cycles.

You have at least two options:

Avoiding circular references

Ignoring circular references

I’ll assume that option 1 (which is usually ideal) it’s not viable for you.

Option 2 is literally a little statement in the Startup class, in the ConfigureServices method (this is for ASP.NET Core 6+):

services.AddControllers().AddJsonOptions(x =>

                x.JsonSerializerOptions.ReferenceHandler = ReferenceHandler.IgnoreCycles);

If you use ASP.NET Core 5:

services.AddControllers().AddJsonOptions(x =>

   x.JsonSerializerOptions.ReferenceHandler = ReferenceHandler.Preserve);

   

   

If you are using ASP.NET Core 3.1 or less, you can do the following:

Install the library: Microsoft.AspNetCore.Mvc.NewtonsoftJson (install the corresponding version, if you have ASP.NET Core 3.1, you install version 3.1 of the library)

Then, in ConfigureServices:

services.AddControllers().AddNewtonsoftJson(x => 

 x.SerializerSettings.ReferenceLoopHandling = Newtonsoft.Json.ReferenceLoopHandling.Ignore);

修復不同版本的 ASP.NET Core 中“檢測到可能的對象循環”錯誤

為了修復錯誤：

System.Text.Json.JsonException: 檢測到可能的對象循環。這可能是由於循環或對象深度大於最大允許深度 32。考慮在 JsonSerializerOptions 上使用 ReferenceHandler.Preserve 以支持循環。

你至少有兩個選擇：

避免循環引用

忽略循環引用

我會假設選項 1（通常是理想的）對您來說不可行。

選項 2 實際上是 Startup 類中的一個小聲明，在 ConfigureServices 方法中（這是針對ASP.NET Core 6+）：

services.AddControllers().AddJsonOptions(x =>

                x.JsonSerializerOptions.ReferenceHandler = ReferenceHandler.IgnoreCycles);

如果您使用ASP.NET Core 5：

services.AddControllers().AddJsonOptions(x =>

   x.JsonSerializerOptions.ReferenceHandler = ReferenceHandler.Preserve);

如果您使用的是ASP.NET Core 3.1 或更低版本，則可以執行以下操作：

安裝庫：Microsoft.AspNetCore.Mvc.NewtonsoftJson（安裝對應版本，如果有ASP.NET Core 3.1，則安裝3.1版本的庫）

然後，在配置服務中：

services.AddControllers().AddNewtonsoftJson(x => 

 x.SerializerSettings.ReferenceLoopHandling = Newtonsoft.Json.ReferenceLoopHandling.Ignore);

 

異常的改善: 指定的路徑、檔名，或是兩者都太長。完整的檔名必須少於 260 個字元，並且目錄名稱必須少於 248 個字元

在 VS2019 中發行網站時出現錯誤 "指定的路徑、檔名，或是兩者都太長。完整的檔名必須少於 260 個字元，並且目錄名稱必須少於 248 個字元。", 造成發佈失敗。

解決方法:

修改環境變數 TEMP 及 TMP 為 C:\TEMP ,獲得改善。

不一定要用路徑 C:\TEMP, 但是要儘量的簡短。

iTextsharp barcode example

iText : v5.5.13.2

protected void submitPdf_Click(object sender, EventArgs e) {
	BarCodeGenerate();
}

/// 

/// Generates the new page with barcode128.
/// 
public void BarCodeGenerate() {
	Document doc = new Document(PageSize.A4.Rotate(), 50, 50, 20, 20);
	PdfWriter writer = PdfWriter.GetInstance(doc, new FileStream(@"c:\temp\BarCodeQRCode.pdf", FileMode.Create));
	doc.Open();
	PdfContentByte cb = writer.DirectContent;
	PdfContentByte cb39 = writer.DirectContent;

	Paragraph pa = new Paragraph();
	Barcode128 barcode = new Barcode128();
	barcode.CodeType = Barcode.CODE128_UCC;
	barcode.Code = "hello barcode - code128";
	iTextSharp.text.Image barcodeImage = barcode.CreateImageWithBarcode(cb, null, null);
	barcodeImage.ScalePercent(100f);
	barcodeImage.Alignment = Element.ALIGN_CENTER;
	pa.Add(barcodeImage);

	BaseFont fontChinese = BaseFont.CreateFont("C:/Windows/Fonts/STSONG.TTF", BaseFont.IDENTITY_H, BaseFont.EMBEDDED);
	Font normalFont = new Font(fontChinese, 12);

	//float[] w = { 5f, 15f, 6f, 10f };
	float[] w = {
			Convert.ToSingle(PageSize.A4.Width * 0.4),
			Convert.ToSingle(PageSize.A4.Width * 0.3),
			Convert.ToSingle(PageSize.A4.Width * 0.3)
		};
	PdfPTable table = new PdfPTable(w);
	table.DefaultCell.Border = iTextSharp.text.Rectangle.NO_BORDER;
	table.DefaultCell.BorderWidth = 0;
	table.DefaultCell.BorderColor = new BaseColor(0, 0, 0);
	table.DefaultCell.Padding = 4;
	table.DefaultCell.SpaceCharRatio = 4;
	table.WidthPercentage = 100;
	table.DefaultCell.HorizontalAlignment = iTextSharp.text.Element.ALIGN_LEFT;

	PdfPCell cell = new PdfPCell(new Phrase("Create a table with all default settings"));
	cell.Border = Rectangle.TOP_BORDER + Rectangle.BOTTOM_BORDER + Rectangle.LEFT_BORDER + Rectangle.RIGHT_BORDER;
	cell.HorizontalAlignment = Rectangle.ALIGN_CENTER;
	table.AddCell(cell);

	var aa = new Paragraph("aaa", normalFont);

	cell = new PdfPCell(new Phrase("Create a table 中文字的測試with all default settings", normalFont));
	cell.Border = Rectangle.TOP_BORDER + Rectangle.BOTTOM_BORDER + Rectangle.LEFT_BORDER + Rectangle.RIGHT_BORDER;
	cell.HorizontalAlignment = Rectangle.ALIGN_CENTER;
	table.AddCell(cell);

	cell = new PdfPCell(new Phrase("Create a table with all default settings"));
	cell.Border = Rectangle.TOP_BORDER + Rectangle.BOTTOM_BORDER + Rectangle.LEFT_BORDER + Rectangle.RIGHT_BORDER;
	cell.HorizontalAlignment = Rectangle.ALIGN_CENTER;
	table.AddCell(cell);

	cell = new PdfPCell(new Phrase("Create a table with all default settings"));
	cell.Border = Rectangle.TOP_BORDER + Rectangle.BOTTOM_BORDER + Rectangle.LEFT_BORDER + Rectangle.RIGHT_BORDER;
	cell.HorizontalAlignment = Rectangle.ALIGN_CENTER;
	table.AddCell(cell);
	doc.Add(table);


	float[] w2 = {
			Convert.ToSingle(PageSize.A4.Width * 0.4),
			Convert.ToSingle(PageSize.A4.Width * 0.2),
			Convert.ToSingle(PageSize.A4.Width * 0.1),
			Convert.ToSingle(PageSize.A4.Width * 0.3)
		};

	//float[] w2 = { 25f, 15f, 30f, 10f };
	table = new PdfPTable(w2);
	table.WidthPercentage = 100;

	cell = new PdfPCell(new Phrase("Create a table with all default settings"));
	cell.Border = Rectangle.TOP_BORDER + Rectangle.BOTTOM_BORDER + Rectangle.LEFT_BORDER + Rectangle.RIGHT_BORDER;
	cell.HorizontalAlignment = Rectangle.ALIGN_CENTER;
	//cell.FixedHeight = 10f;
	table.AddCell(cell);

	cell = new PdfPCell(barcodeImage, true);
	cell.Border = Rectangle.TOP_BORDER + Rectangle.BOTTOM_BORDER + Rectangle.LEFT_BORDER + Rectangle.RIGHT_BORDER;
	cell.HorizontalAlignment = Rectangle.ALIGN_CENTER;
	cell.Padding = 5f;
	//cell.FixedHeight = 10f;
	table.AddCell(cell);

	cell = new PdfPCell(new Phrase("Create a table with all default settings"));
	cell.Border = Rectangle.TOP_BORDER + Rectangle.BOTTOM_BORDER + Rectangle.LEFT_BORDER + Rectangle.RIGHT_BORDER;
	cell.HorizontalAlignment = Rectangle.ALIGN_CENTER;
	//cell.FixedHeight = 10f;
	table.AddCell(cell);

	cell = new PdfPCell(new Phrase("Create a table with all default settings"));
	cell.Border = Rectangle.TOP_BORDER + Rectangle.BOTTOM_BORDER + Rectangle.LEFT_BORDER + Rectangle.RIGHT_BORDER;
	cell.HorizontalAlignment = Rectangle.ALIGN_CENTER;
	//cell.FixedHeight = 10f;
	table.AddCell(cell);

	doc.Add(table);

	Barcode39 code39 = new Barcode39();
	code39.Code = "314159265";
	//code39.CodeType = Barcode.CODE128_UCC;
	code39.StartStopText = true;
	code39.GenerateChecksum = true;
	code39.Extended = true;
	iTextSharp.text.Image code39Image = code39.CreateImageWithBarcode(cb39, null, null);
	//iTextSharp.text.Image code39Image = code39.CreateDrawingImage(System.Drawing.Color.Black, System.Drawing.Color.White);
	pa.Add(code39Image);


	cell = new PdfPCell(new Phrase("Create a table with all default settings"));
	cell.Border = Rectangle.TOP_BORDER + Rectangle.BOTTOM_BORDER + Rectangle.LEFT_BORDER + Rectangle.RIGHT_BORDER;
	cell.HorizontalAlignment = Rectangle.ALIGN_CENTER;
	//cell.FixedHeight = 10f;
	table.AddCell(cell);

	cell = new PdfPCell(code39Image, true);
	cell.Border = Rectangle.TOP_BORDER + Rectangle.BOTTOM_BORDER + Rectangle.LEFT_BORDER + Rectangle.RIGHT_BORDER;
	cell.HorizontalAlignment = Rectangle.ALIGN_CENTER;
	cell.Padding = 5f;
	//cell.FixedHeight = 10f;
	table.AddCell(cell);

	cell = new PdfPCell(new Phrase("Create a table with all default settings"));
	cell.Border = Rectangle.TOP_BORDER + Rectangle.BOTTOM_BORDER + Rectangle.LEFT_BORDER + Rectangle.RIGHT_BORDER;
	cell.HorizontalAlignment = Rectangle.ALIGN_CENTER;
	//cell.FixedHeight = 10f;
	table.AddCell(cell);

	cell = new PdfPCell(new Phrase("Create a table with all default settings"));
	cell.Border = Rectangle.TOP_BORDER + Rectangle.BOTTOM_BORDER + Rectangle.LEFT_BORDER + Rectangle.RIGHT_BORDER;
	cell.HorizontalAlignment = Rectangle.ALIGN_CENTER;
	//cell.FixedHeight = 10f;
	table.AddCell(cell);

	table.AddCell(cell);
	doc.Add(table);
	table.AddCell(cell);
	doc.Add(table);
	table.AddCell(cell);
	doc.Add(table);


	code39.StartStopText = true;
	code39.GenerateChecksum = false;
	code39.Extended = true;
	code39Image = code39.CreateImageWithBarcode(cb39, null, null);
	pa.Add(code39Image);

	table.AddCell(cell);
	doc.Add(table);
	table.AddCell(cell);
	doc.Add(table);
	table.AddCell(cell);
	doc.Add(table);

	BarcodeQRCode qrcode = new BarcodeQRCode("hello barcode - QrCode", 100, 100, null);
	iTextSharp.text.Image grImage = qrcode.GetImage();
	pa.Add(grImage);


	/*
	https://dotblogs.com.tw/kevinya/2016/01/13/104010

	由於 iTextSharp 內建的 QRCode 類別對於中文內容的支援度較差，
	需經過幾道 override 的程序改寫才可存中文，所以在此直接採用
	第三方元件 MessagingToolkit.QRCode。

	利用此第三方元件的QRCodeEncoder物件即可產生QRCode的點陣圖Bitmap，
	再將bitmap轉換成iTextSharp.text.Image即可加入到pdf之中：

		QRCodeEncoder chtEncoder = new QRCodeEncoder();
		//第三方先產生bitmap
		Bitmap qrBitmap1 = chtEncoder.Encode("qrcode裝中文內容"); //將內容轉碼成 QR code            
		//再將bitmap轉換成iTextSharp.text.Image
		iTextSharp.text.Image qrImage1 = iTextSharp.text.Image.GetInstance(qrBitmap1, BaseColor.BLACK);
		qrImage1.ScalePercent(50);
		qrImage1.Alignment = Element.ALIGN_RIGHT;//透過Image.Alignment來設定靠左靠右
		pa.Add(qrImage1);
		doc.Add(pa);
		doc.Close();

	*/

	doc.Add(pa);

	doc.Close();
}