The type judgment of "C #" Decimal!

I write these kinds of methods or functions, it is inevitable that some errors or bugs exist, please do a lot of advice! Shixiang9076@sina.com.

Using System;
Using System.Drawing;
Using System.Collections;
Using System.ComponentModel;
Using System.Windows.Forms;
Using System.Data;

Namespace Winmarket
{
<summary>
Summary description of the Classfun.
</summary>
public class Classfun
{
private bool Isbool;

Public Classfun ()
{
//
TODO: Add constructor logic here
//
}
--------------judge whether it is a decimal type------------

public bool Isdecimal (string TBstr0)
{
String intstr0= "1234567890";
String Intsign0,strint,strdecimal;
int intindex0,intsubstr,indexint;
int decimalbool=0;
int db=0;
BOOL BF,BL;
if (tbstr0.length>2)
{
Intindex0=tbstr0.indexof (".");
if (intindex0!=-1)
{
String strarr= ".";
Char[] Chararr=strarr.tochararray ();
String[] Numarr=tbstr0.split (Chararr);
Indexint=numarr.getupperbound (0);
if (indexint>1)
{
decimalbool=1;
}
Else
{
Strint=numarr[0]. ToString ();
STRDECIMAL=NUMARR[1]. ToString ();
---integral part--
if (strint.length>0)
{
if (strint.length==1)
{
Intsubstr=intstr0.indexof (Strint);
if (intsubstr!=-1)
{
Bf=true;
}
Else
{
Bf=false;
}
}
Else
{
for (int i=0;i<=strint.length-1;i++)
{
Intsign0=strint.substring (i,1). ToString ();
Intsubstr=intstr0.indexof (IntSign0);
if (intsubstr!=-1)
{
db=db+0;
}
Else
{
db=i+1;
Break
}
}

if (db==0)
{
Bf=true;
}
Else
{
Bf=false;
}
}
}
Else
{
Bf=true;
}
----A small number of parts--
if (strdecimal.length>0)
{
for (int j=0;j<=strdecimal.length-1;j++)
{
Intsign0=strdecimal.substring (j,1). ToString ();
Intsubstr=intstr0.indexof (IntSign0);
if (intsubstr!=-1)
{
db=db+0;
}
Else
{
db=j+1;
Break
}
}
if (db==0)
{
Bl=true;
}
Else
{
Bl=false;
}
}
Else
{
Bl=false;
}
if ((BF&AMP;&AMP;BL) ==true)
{
decimalbool=0;
}
Else
{
decimalbool=1;
}

}

}
Else
{
decimalbool=1;
}

}
Else
{
decimalbool=1;
}

if (decimalbool==0)
{
Isbool=true;
}
Else
{
Isbool=false;
}

return isbool;
}

}
}