Difference between revisions of "Visual Basic .net"

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(→‎RS-232)
(→‎Datatypes)
Line 41: Line 41:
 
==RS-232==
 
==RS-232==
 
==Datatypes==
 
==Datatypes==
 +
<table cellspacing="0" cellpadding="4" border="1">
 +
<tr>
 +
<td valign="top"><b>Visual Basic type</b></td>
 +
<td valign="top"><b>.NET Runtime type</b></td>
 +
<td valign="top"><b>structure Storage size</b></td>
 +
<td valign="top"><b>Value range</b></td>
 +
</tr>
 +
<tr>
 +
<td valign="top"><code>Boolean</code></td>
 +
<td valign="top"><code>System.Boolean</code></td>
 +
<td valign="top">4 bytes</td>
 +
<td valign="top">True or False</td>
 +
</tr>
 +
<tr>
 +
<td valign="top"><code>Byte</code></td>
 +
<td valign="top"><code>System.Byte</code></td>
 +
<td valign="top">1 byte</td>
 +
<td valign="top">0 to 255 (unsigned)</td>
 +
</tr>
 +
<tr>
 +
<td valign="top"><code>Char</code></td>
 +
<td valign="top"><code>System.Char</code></td>
 +
<td valign="top">2 bytes</td>
 +
<td valign="top">0 to 65535 (unsigned)</td>
 +
</tr>
 +
<tr>
 +
<td valign="top"><code>Date</code></td>
 +
<td valign="top"><code>System.DateTime</code></td>
 +
<td valign="top">8 bytes</td>
 +
<td valign="top">January 1, 1 CE to December 31, 9999</td>
 +
</tr>
 +
<tr>
 +
<td valign="top"><code>Decimal</code></td>
 +
<td valign="top"><code>System.Decimal</code></td>
 +
<td valign="top">12 bytes</td>
 +
<td valign="top">+/-79,228,162,514,264,337,593,543,950,335 with no decimal point;
 +
    +/-7.9228162514264337593543950335 with 28 places to the right of the decimal;
 +
    smallest non-zero number is +/-0.0000000000000000000000000001
 +
</td>
 +
</tr>
 +
<tr>
 +
<td valign="top"><code>Double</code></td>
 +
<td valign="top"><code>System.Double</code> </td>
 +
<td valign="top">8 bytes </td>
 +
<td valign="top">-1.79769313486231E308 to -4.94065645841247E-324 for negative
 +
    values; 4.94065645841247E-324 to 1.79769313486232E308 for positive values
 +
</td>
 +
</tr>
 +
<tr>
 +
<td valign="top"><code>Integer</code> </td>
 +
<td valign="top"><code>System.Int32</code> </td>
 +
<td valign="top">4 bytes </td>
 +
<td valign="top">-2,147,483,648 to 2,147,483,647 </td>
 +
</tr>
 +
<tr>
 +
<td valign="top"><code>Long</code> </td>
 +
<td valign="top"><code>System.Int64</code> </td>
 +
<td valign="top">8 bytes </td>
 +
<td valign="top">-9,223,372,036,854,775,808 to 9,223,372,036,854,775,807 </td>
 +
</tr>
 +
<tr>
 +
<td valign="top"><code>Object</code> </td>
 +
<td valign="top"><code>System.Object</code> (class) </td>
 +
<td valign="top">4 bytes </td>
 +
<td valign="top">Any type can be stored in a variable of type <code>Object</code> </td>
 +
</tr>
 +
<tr>
 +
<td valign="top"><code>Short</code> </td>
 +
<td valign="top"><code>System.Int16</code> </td>
 +
<td valign="top">2 bytes </td>
 +
<td valign="top">-32,768 to 32,767 </td>
 +
</tr>
 +
<tr>
 +
<td valign="top"><code>Single</code> </td>
 +
<td valign="top"><code>System.Single</code> </td>
 +
<td valign="top">4 bytes </td>
 +
<td valign="top">-3.402823E38 to -1.401298E-45 for negative values; 1.401298E-45 to
 +
    3.402823E38 for positive values
 +
</td>
 +
</tr>
 +
<tr>
 +
<td valign="top"><code>String</code> </td>
 +
<td valign="top"><code>System.String</code> (class) </td>
 +
<td valign="top">10 bytes + (2 * string length) </td>
 +
<td valign="top">0 to approximately two billion Unicode characters </td>
 +
</tr>
 +
<tr>
 +
<td valign="top">User-Defined Type (structure) </td>
 +
<td valign="top">(inherits from <code>System.ValueType</code>) </td>
 +
<td valign="top">Sum of the sizes of its members </td>
 +
<td valign="top">Each member of the structure has a range determined by its data type and independent
 +
    of the ranges of the other members
 +
</td>
 +
</tr>
 +
</table>

Revision as of 08:59, 27 December 2009

Graphics

Files

Reading text files line by line:
Dim f1 As Long
dim filestring as string

f1 = FreeFile()
FileOpen(f1, My.Application.Info.DirectoryPath & "\filename.txt", OpenMode.Input)
Do Until EOF(f1)

filestring=LineInput(f1)

Loop
FileClose(f1)
 Note: My.Application.Info.DirectoryPath & "\filename.txt" may be replaced by "C:\some_path\file.txt"


Writing text files line by line:
Dim f1 As Long

f1 = FreeFile()
FileOpen(f1, My.Application.Info.DirectoryPath & "\filename.txt", OpenMode.Output
Print(f1, "This is line 1")
Print(f1, "This is line 2")
FileClose(f1)

Arrays

Threading / Parallel

Loops

Conditionals

Math

RS-232

Datatypes

Visual Basic type .NET Runtime type structure Storage size Value range
Boolean System.Boolean 4 bytes True or False
Byte System.Byte 1 byte 0 to 255 (unsigned)
Char System.Char 2 bytes 0 to 65535 (unsigned)
Date System.DateTime 8 bytes January 1, 1 CE to December 31, 9999
Decimal System.Decimal 12 bytes +/-79,228,162,514,264,337,593,543,950,335 with no decimal point; 
   +/-7.9228162514264337593543950335 with 28 places to the right of the decimal; 
   smallest non-zero number is +/-0.0000000000000000000000000001
Double System.Double 8 bytes -1.79769313486231E308 to -4.94065645841247E-324 for negative 
   values; 4.94065645841247E-324 to 1.79769313486232E308 for positive values
Integer System.Int32 4 bytes -2,147,483,648 to 2,147,483,647
Long System.Int64 8 bytes -9,223,372,036,854,775,808 to 9,223,372,036,854,775,807
Object System.Object (class) 4 bytes Any type can be stored in a variable of type Object
Short System.Int16 2 bytes -32,768 to 32,767
Single System.Single 4 bytes -3.402823E38 to -1.401298E-45 for negative values; 1.401298E-45 to 
   3.402823E38 for positive values
String System.String (class) 10 bytes + (2 * string length) 0 to approximately two billion Unicode characters
User-Defined Type (structure) (inherits from System.ValueType) Sum of the sizes of its members Each member of the structure has a range determined by its data type and independent 
   of the ranges of the other members
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