How to fix FormatException and InvalidCastException errors

[rkopja]

Can anyone tell me why i get this? I just setup a Intranet and I have no problem using Firefox or even Google chrome to get into it when i use Internet Explorer i get the following error:
Stack Trace:


[FormatException : Input string was not in a correct format.]
Microsoft.Visua lBasic.Compiler Services.Conver sions.ParseDoub le(String Value, NumberFormatInf o NumberFormat) +188
Microsoft.Visua lBasic.Compiler Services.Conver sions.ToDouble( String Value, NumberFormatInf o NumberFormat) +68

[InvalidCastExce ption: Conversion from string "" to type 'Double' is not valid.]
Microsoft.Visua lBasic.Compiler Services.Conver sions.ToDouble( String Value, NumberFormatInf o NumberFormat) +212
ASP.default2_as px.Page_Load(Ob ject Source, EventArgs E) +112
System.Web.Util .CalliHelper.Ev entArgFunctionC aller(IntPtr fp, Object o, Object t, EventArgs e) +14
System.Web.Util .CalliEventHand lerDelegateProx y.Callback(Obje ct sender, EventArgs e) +35
System.Web.UI.C ontrol.OnLoad(E ventArgs e) +91
System.Web.UI.C ontrol.LoadRecu rsive() +74
System.Web.UI.P age.ProcessRequ estMain(Boolean includeStagesBe foreAsyncPoint, Boolean includeStagesAf terAsyncPoint) +2207

[tlhintoq]

Error: InvalidCastExce ption: Conversion from string "" to type 'Double' is not valid.

Is there such a number as "" ? No. Therefore you cannot cast "" to a number.
Range checking is so often overlooked. One cannot assume that you always have values in the range you expect. You really should check that your strings contain something before trying to process them.

Error: FormatException : Input string was not in a correct format.

You tried to parse something that wasn't a number. This is a continuation of the error before it (answered above)

[medicinesoup]

I don't know where in your code a string is being placed in a double variable, but try wrapping your input in a val command.

'VB
Dim dblMyDouble as Double = Val("3 is my number")

//C#
double dblMyDouble = Conversion.Val("3 is my number");

Even if the string is "" or even a non-number like "hello" it will put a zero in your double variable, so if the string is something invalid, your program will still keep going with no errors.