problem converting VB to C#

Question

User5363102 posted

HI Guys,

I am writing server side validation in c# which was in VB

the code in VB is

If Not IsNumeric(Args.Values("BookQty")) Then
    Args.Cancel = True
    EditMSG.Text = "• Quantity is not numeric"

If Args.Values("BookQty") < 0 Then
      Args.Cancel = True
      EditMSG.Text = "&bull; Quantity is out of range"
    End If 

the code I converted to c# using converter

These are two errors
 

if (!IsNumeric(Args.NewValues["BookQty"]))
        {
            Args.Cancel = true;
            EditMSG.Text = "•Quantity is not numeric"; 

The name 'IsNumeric' does not exist in the current context	

 if ((Args.Values["BookQty"] < 0))
        {
            Args.Cancel = true;
            EditMSG.Text = "• Quantity is out of range";
        }

Operator '<' cannot be applied to operands of type 'object' and 'int'	

can anybody please help me. 

Answer 1

User56914146 posted

The problem is that you need to create a method called IsNumeric to check if the value is numeric.. for example...

private bool IsNumeric(Object obj )

{

int result;

bool isNumeric = int.TryParse(obj.ToString(), out result);

return isNumeric;

}

Your other problem is that you are trying to compare an object type to an int type... You need to cast or parse the value to an int.. for example.....

if ((int.Parse(Args.Values["BookQty"]) < 0))

{

Args.Cancel = true;

EditMSG.Text = "• Quantity is out of range";

}

Hope this helps

Answer 2

User5363102 posted

I have already tried int.parse  if ((int.Parse(Args.Values["BookQty"]) < 0))

 but the error still is the same

thank you though 

The problem is that you need to create a method called IsNumeric to check if the value is numeric.. for example...

private bool IsNumeric(Object obj )

{

int result;

bool isNumeric = int.TryParse(obj.ToString(), out result);

return isNumeric;

}

Your other problem is that you are trying to compare an object type to an int type... You need to cast or parse the value to an int.. for example.....

if ((int.Parse(Args.Values["BookQty"]) < 0))

{

Args.Cancel = true;

EditMSG.Text = "• Quantity is out of range";

}

Hope this helps

 

Answer 3

User56914146 posted

try adding ToString()...

if(int.Parse(Args.Values["BookQty"].ToString())< 0)

Answer 4

User242249085 posted

The problem is that you need to create a method called IsNumeric to check if the value is numeric..

 

Actually you don't.

You can use the VB method:

- Add Microsoft.VisualBasic.dll as a project reference.

- Call as: 

if (Microsoft.VisualBasic.Information.IsNumeric(val) {
  ...

 

Answer 5

User5363102 posted

 I am still getting the same error

if ((int.Parse(Args.Values["BookID"].ToString()) == "")) 

Error: Operator '==' cannot be applied to operands of type 'int' and 'string'.

if (!IsNumeric(Args.Values["BookPrice"])

Error : The name 'IsNumeric' does not exist in the current context 

This is after adding the reference Microsoft.Visual basic.

I am just  looking to write a required field validator using the details view Item Inserting event here is the signature Validate_Insert_Data(object Src, DetailsViewInsertEventArgs Args)

can anybody help me with an example.

thanks in advance ......... 

Answer 6

User-1910946339 posted

Hi, don't know why you can't get IsNumeric to work but you don't need it.  Try changing

if (!IsNumeric(Args.NewValues["BookQty"]))
        {
            Args.Cancel = true;
            EditMSG.Text = "•Quantity is not numeric"; 

 if ((Args.Values["BookQty"] < 0))
        {
            Args.Cancel = true;
            EditMSG.Text = "• Quantity is out of range";
        }

to

int bookQty;
bool quantityIsAnInt = int.TryParse(Args.Values["BookQty"], out bookQty);
if (!quantityIsAnInt) {
   Args.Cancel = true;
   EditMSG.Text = ....
...  exit from the routine
}
if (bookQty < 0) {
   Args.Cancel = true;
   EditMSG.Text = ...
... exit from the routine
}
// At this point bookQty is a valid int

 

Answer 7

User242249085 posted

if (!IsNumeric(Args.Values["BookPrice"])

Error : The name 'IsNumeric' does not exist in the current context 

 

In C# you have to call a static method using the name of the class, this is why I wrote "Microsoft.VisualBasic.Information.IsNumeric" (this can be shortened with a using directive).

if ((int.Parse(Args.Values["BookID"].ToString()) == "")) 

Error: Operator '==' cannot be applied to operands of type 'int' and 'string'.

 

What are you trying to check for here?

If you want to check whether the conversion worked, then you are better off with int.TryParse (as noted by another reply).

If you want to check if converting makes sense, then you need to check before the call: 

string str = Args.Values["BookID"].ToString();
if (!String.IsEmptyOrNull(str)) {
  int res;
  if (int.TryParse(str, out res)) {
    // Conversion succeeded.
  }
}

Finally, I note you are calling ToString on the value from Args collection. Why not cast directly to its actual type rather than converting to a string and then parsing to an int?

 

Answer 8

User-16010594 posted

Hi all,

I hv added refernce of Microsoft.VisualBasic.dll (V4.0) for vs 2010 still i m getting error on line

 "double CheckNumericNull =Microsoft.VisualBasic.Conversion.Val(Data);"

Error 170 The type or namespace name 'Conversion' does not exist in the namespace 'Microsoft.VisualBasic' (are you missing an assembly reference?)

Plz help me resolve the error.

I m struggling since yesterday.

Thanx all in advance

Answer 9

User397347636 posted

You should be able to call it like that, but if you want to avoid having the VisualBasic namespace in your project you can use a helper class we use in one of our converters to replace calls to 'Val':

//----------------------------------------------------------------------------------------
//	Copyright © 2003 - 2013 Tangible Software Solutions Inc.
//	This class can be used by anyone provided that the copyright notice remains intact.
//
//	This class simulates the behavior of the classic VB 'Val' function.
//----------------------------------------------------------------------------------------
public static class SimulateVal
{
	public static double Val(string expression)
	{
		if (expression == null)
			return 0;

		//try the entire string, then progressively smaller
		//substrings to simulate the behavior of VB's 'Val',
		//which ignores trailing characters after a recognizable value:
		for (int size = expression.Length; size > 0; size--)
		{
			double testDouble;
			if (double.TryParse(expression.Substring(0, size), out testDouble))
				return testDouble;
		}

		//no value is recognized, so return 0:
		return 0;
	}
	public static double Val(object expression)
	{
		if (expression == null)
			return 0;

		double testDouble;
		if (double.TryParse(expression.ToString(), out testDouble))
			return testDouble;

		//VB's 'Val' function returns -1 for 'true':
		bool testBool;
		if (bool.TryParse(expression.ToString(), out testBool))
			return testBool ? -1 : 0;

		//VB's 'Val' function returns the day of the month for dates:
		System.DateTime testDate;
		if (System.DateTime.TryParse(expression.ToString(), out testDate))
			return testDate.Day;

		//no value is recognized, so return 0:
		return 0;
	}
	public static int Val(char expression)
	{
		int testInt;
		if (int.TryParse(expression.ToString(), out testInt))
			return testInt;
		else
			return 0;
	}
}