isnumeric in c sharp

[crowl]

I have a pocket pc project in c#.

From a textbox i have to verify if the input is numeric. I have found
in the msdn a sample like this: textbox1.numeric = true / false. But
this do not work in my environment.

If I convert the textbox content explicit to a numeric value, and is
is not numeric, the program ran into the error handler (try catch).
This is not what I want!

For example: 2 textbox, 1 button
If the user click the button, the program should proof if the content
of the textboxes is numeric, if not, it should use a standard value
and then go on.

A nice method like 'isnumeric' would be glad.

Thanks for all assistance.

[Dmitriy Lapshin [C# / .NET MVP]]

Hi,

You can attempt to feed the textbox's Text property value to the Parse
method of the Int32 type, and catch the FormatException, OverflowException
and optionally ArgumentNullException (this one is unlikely to be raised).
If any of the exceptions has been thrown, the textbox's text is not a valid
integer.

This approach works the same way for Double, Decimal or any other type
supporting the Parse method.

--
Dmitriy Lapshin [C# / .NET MVP]
X-Unity Test Studio
http://www.x-unity.net/teststudio.aspx
Bring the power of unit testing to VS .NET IDE

"crowl" <cr***@gmx.de> wrote in message
news:e1**************************@posting.google.c om...

I have a pocket pc project in c#.

From a textbox i have to verify if the input is numeric. I have found
in the msdn a sample like this: textbox1.numeric = true / false. But
this do not work in my environment.

If I convert the textbox content explicit to a numeric value, and is
is not numeric, the program ran into the error handler (try catch).
This is not what I want!

For example: 2 textbox, 1 button
If the user click the button, the program should proof if the content
of the textboxes is numeric, if not, it should use a standard value
and then go on.

A nice method like 'isnumeric' would be glad.

Thanks for all assistance.

[Jackson Davis [MSFT]]

Is there a reason you can't use a try / catch block with System.Convert

such as

void Button_Click(object sender, eventargs e

// verify the textbox contains an intege
tr

int i = System.Convert.ToInt32(TextBox1.Text, 10)
// if you get here then the i contains the integer value of TextBox1.Tex

catch (System.FormatException e

// the conversion failed so use the default value
i = defaultValue

// Continue processing
Jackson Davis [msft
-
This posting is provided "AS IS" with no warranties, and confers no right
Samples are subject to the terms specified a
http://www.microsoft.com/info/cpyright.ht

[Dmitriy Lapshin [C# / .NET MVP]]

Hello Jackson,

I think catching FormatException only would be an unreliable solution.
Imagine the user has typed something like "9999999999999999999999999999" to
the textbox. In this case, I suppose an OverflowException instance will be
thrown upon calling the ToInt32 method, not a FormatException.

--
Dmitriy Lapshin [C# / .NET MVP]
X-Unity Test Studio
http://www.x-unity.net/teststudio.aspx
Bring the power of unit testing to VS .NET IDE

"Jackson Davis [MSFT]" <an*******@discussions.microsoft.com> wrote in
message news:81**********************************@microsof t.com...

Is there a reason you can't use a try / catch block with System.Convert?

such as:

void Button_Click(object sender, eventargs e)
{
// verify the textbox contains an integer
try
{
int i = System.Convert.ToInt32(TextBox1.Text, 10);
// if you get here then the i contains the integer value of TextBox1.Text }
catch (System.FormatException e)
{
// the conversion failed so use the default value.
i = defaultValue;
}
// Continue processing.
}

Jackson Davis [msft]
--
This posting is provided "AS IS" with no warranties, and confers no rights
Samples are subject to the terms specified at
http://www.microsoft.com/info/cpyright.htm

[mikeb]

crowl wrote:

I have a pocket pc project in c#.

From a textbox i have to verify if the input is numeric. I have found
in the msdn a sample like this: textbox1.numeric = true / false. But
this do not work in my environment.

If I convert the textbox content explicit to a numeric value, and is
is not numeric, the program ran into the error handler (try catch).
This is not what I want!

For example: 2 textbox, 1 button
If the user click the button, the program should proof if the content
of the textboxes is numeric, if not, it should use a standard value
and then go on.

A nice method like 'isnumeric' would be glad.

You can use VB.NET's IsNumeric method. Add a reference to
Microsoft.VisualBasic.dll, then call the static method:

Microsoft.VisualBasic.Information.IsNumeric( object)

--
mikeb

[Shawn B.]

Here is my adaptation to the IL of the VB "IsNumeric" method. Of course,
this is not as exhausting. There is a lot of IL I can't make sense of and a
lot of Locale stuff I didn't even attempt. Assuming you using ASCII
characters in the string and all others, numerics, this should work.
---------------------------------------------------

using System;

namespace CSharpInformation
{

public class Information
{
public static bool IsNumeric(object expression) {

IConvertible convertible = null;
TypeCode typecode;
string text;
double num;
bool result = false;
char chr;

if ((expression as IConvertible) != null) {
convertible = (IConvertible)expression;
}

if (convertible == null) {
if ((expression as char[]) != null) {
expression = new string((char[])expression);
}
else {
return false;
}
}

typecode = convertible.GetTypeCode();

if (typecode == TypeCode.String || typecode == TypeCode.Char) {
text = convertible.ToString(null);

try {
for (int i=0; i<text.Length; i++) {
chr = Convert.ToChar(text.Substring(i, 1));

if (char.IsNumber(chr)) {
result = true;
}
else if ((int)chr >= 'a' && (int)chr <= 'f') {
result = true;
}
else if ((int)chr >= 'A' && (int)chr <= 'F') {
result = true;
}
else {
result = false;
}

if (result == false) {
break;
}
}
}
catch(Exception) {
return false;
}

if (result == false) {
result = double.TryParse(text,
System.Globalization.NumberStyles.Any, null, out num);
}
}

if (result == false) {
result = IsNumericTypeCode(typecode);
}

return result;
}

internal static bool IsNumericTypeCode(TypeCode typeCode) {
bool result = false;

switch (typeCode) {
case TypeCode.Decimal:
case TypeCode.Double:
case TypeCode.Int16:
case TypeCode.Int32:
case TypeCode.Int64:
case TypeCode.Single:
case TypeCode.UInt16:
case TypeCode.UInt32:
case TypeCode.UInt64:
result = true;
break;

default:
result = false;
break;
}

return result;
}
}
}

[Ruchi Gupta]

public static bool IsNumeric(object value)
{
try
{
double d = System.Double.Parse(value.ToString(),
System.Globalization.NumberStyles.Any);
return true;
}
catch (FormatException)
{
return false;
}
}


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[Dave Lech]

Here is some code that doesn't rely on error trapping:

public static bool IsNumeric(string stringToTest)

{

double newVal;

return double.TryParse(stringToTest, NumberStyles.Any,
NumberFormatInfo.InvariantInfo, out newVal);

}

"crowl" <cr***@gmx.de> wrote in message
news:e1**************************@posting.google.c om...

I have a pocket pc project in c#.

From a textbox i have to verify if the input is numeric. I have found
in the msdn a sample like this: textbox1.numeric = true / false. But
this do not work in my environment.

If I convert the textbox content explicit to a numeric value, and is
is not numeric, the program ran into the error handler (try catch).
This is not what I want!

For example: 2 textbox, 1 button
If the user click the button, the program should proof if the content
of the textboxes is numeric, if not, it should use a standard value
and then go on.

A nice method like 'isnumeric' would be glad.

Thanks for all assistance.

[Shawn B.]

This won't detect Hexadecimal values.
Thanks,
Shawn

"Dave Lech" <da*******@tyson.com> wrote in message
news:e4**************@TK2MSFTNGP11.phx.gbl...

Here is some code that doesn't rely on error trapping:

public static bool IsNumeric(string stringToTest)

{

double newVal;

return double.TryParse(stringToTest, NumberStyles.Any,
NumberFormatInfo.InvariantInfo, out newVal);

}

"crowl" <cr***@gmx.de> wrote in message
news:e1**************************@posting.google.c om...

I have a pocket pc project in c#.

From a textbox i have to verify if the input is numeric. I have found
in the msdn a sample like this: textbox1.numeric = true / false. But
this do not work in my environment.

If I convert the textbox content explicit to a numeric value, and is
is not numeric, the program ran into the error handler (try catch).
This is not what I want!

For example: 2 textbox, 1 button
If the user click the button, the program should proof if the content
of the textboxes is numeric, if not, it should use a standard value
and then go on.

A nice method like 'isnumeric' would be glad.

Thanks for all assistance.

[crowl]

Thank you all for the nice ideas!

I think a own methode fits to my need.

Thanks again.

"Shawn B." <le****@html.com> wrote in message news:<#a**************@TK2MSFTNGP09.phx.gbl>...

This won't detect Hexadecimal values.
Thanks,
Shawn

"Dave Lech" <da*******@tyson.com> wrote in message
news:e4**************@TK2MSFTNGP11.phx.gbl...

Here is some code that doesn't rely on error trapping:

public static bool IsNumeric(string stringToTest)

{

double newVal;

return double.TryParse(stringToTest, NumberStyles.Any,
NumberFormatInfo.InvariantInfo, out newVal);

}

"crowl" <cr***@gmx.de> wrote in message
news:e1**************************@posting.google.c om...

I have a pocket pc project in c#.

From a textbox i have to verify if the input is numeric. I have found
in the msdn a sample like this: textbox1.numeric = true / false. But
this do not work in my environment.

If I convert the textbox content explicit to a numeric value, and is
is not numeric, the program ran into the error handler (try catch).
This is not what I want!

For example: 2 textbox, 1 button
If the user click the button, the program should proof if the content
of the textboxes is numeric, if not, it should use a standard value
and then go on.

A nice method like 'isnumeric' would be glad.

Thanks for all assistance.

[Shawn B.]

At the least, I have to admit that the double.TryParse works well and is a 1
liner. Looking at the VB IsNumeric clone I posted above, it is much
simpler.

Thanks,
Shawn

"crowl" <cr***@gmx.de> wrote in message
news:e1**************************@posting.google.c om...

Thank you all for the nice ideas!

I think a own methode fits to my need.

Thanks again.

"Shawn B." <le****@html.com> wrote in message

news:<#a**************@TK2MSFTNGP09.phx.gbl>...

This won't detect Hexadecimal values.
Thanks,
Shawn

"Dave Lech" <da*******@tyson.com> wrote in message
news:e4**************@TK2MSFTNGP11.phx.gbl...

Here is some code that doesn't rely on error trapping:

public static bool IsNumeric(string stringToTest)

{

double newVal;

return double.TryParse(stringToTest, NumberStyles.Any,
NumberFormatInfo.InvariantInfo, out newVal);

}

"crowl" <cr***@gmx.de> wrote in message
news:e1**************************@posting.google.c om...
> I have a pocket pc project in c#.
>
> From a textbox i have to verify if the input is numeric. I have found > in the msdn a sample like this: textbox1.numeric = true / false. But
> this do not work in my environment.
>
> If I convert the textbox content explicit to a numeric value, and is
> is not numeric, the program ran into the error handler (try catch).
> This is not what I want!
>
> For example: 2 textbox, 1 button
> If the user click the button, the program should proof if the content > of the textboxes is numeric, if not, it should use a standard value
> and then go on.
>
> A nice method like 'isnumeric' would be glad.
>
> Thanks for all assistance.