sao vào link này bị lỗi ta
https://members.wcanow.com/transaction_history.aspx
Server Error in '/' Application.
Conversion from type 'DBNull' to type 'Double' is not valid.
Description: An unhandled exception occurred during the execution of the current web request. Please review the stack trace for more information about the error and where it originated in the code.
Exception Details: System.InvalidCastException: Conversion from type 'DBNull' to type 'Double' is not valid.
Source Error:
An unhandled exception was generated during the execution of the current web request. Information regarding the origin and location of the exception can be identified using the exception stack trace below.
Stack Trace:
[InvalidCastException: Conversion from type 'DBNull' to type 'Double' is not valid.]
Microsoft.VisualBasic.CompilerServices.Conversions.ToDouble(Object Value, NumberFormatInfo NumberFormat) +701678
wca.transaction_history.calcadunits() in D:\production\wca\transaction_history.aspx.vb:109
wca.transaction_history.Page_Load(Object sender, EventArgs e) in D:\production\wca\transaction_history.aspx.vb:30
System.Web.UI.Control.OnLoad(EventArgs e) +132
System.Web.UI.Control.LoadRecursive() +66
System.Web.UI.Page.ProcessRequestMain(Boolean includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint) +2428