public string KontratId = "";
Burada veriyi boş alıyorsunuz. Hatanın sebebi budur.
public string KontratId = Request.QueryString("KontratId").ToString();
şeklinde değişken ile alabilirsiniz.
bu şekilde yaptığımda bu seferde aşağıdaki hatayı alıyorum
Server Error in '/' Application.
Compilation Error
Description: An error occurred during the compilation of a resource required to service this request. Please review the following specific error details and modify your source code appropriately.
Compiler Error Message: CS0120: An object reference is required for the non-static field, method, or property 'System.Web.UI.Page.Request.get'
Source Error:
Line 12: {
Line 13: SiteAyar system = new SiteAyar();
Line 14: public string KontratId = Request.QueryString("KontratId").ToString();
Line 15:
Line 16:
Source File: c:\inetpub\vhosts\xxxxx.net.tr\httpdocs\Admin\Kontratdetay.aspx.cs Line: 14
Show Detailed Compiler Output:
Show Complete Compilation Source:
Version Information: Microsoft .NET Framework Version:4.0.30319; ASP.NET Version:4.0.30319.17929