Convert.ToInt32 Method (String)
[ This article is for Windows Phone 8 developers. If you’re developing for Windows 10, see the latest documentation. ]
Converts the specified String representation of a number to an equivalent 32-bit signed integer.
Assembly: mscorlib (in mscorlib.dll)
Parameters
- value
- Type: System.String
A String containing a number to convert.
Return Value
Type: System.Int32A 32-bit signed integer equivalent to the value of value.
-or-
Zero if value is Nothing.
| Exception | Condition |
|---|---|
| FormatException | value does not consist of an optional sign followed by a sequence of digits (zero through nine). |
| OverflowException | value represents a number less than MinValue or greater than MaxValue. |
The return value is the result of invoking the Int32.Parse method on value.
If you prefer not to handle an exception if the conversion fails, you can call the Int32.TryParse method instead. It returns a Boolean value that indicates whether the conversion succeeded or failed.
The following code example converts String representations of 32-bit integers with the ToInt32 method, using default formatting.
' Example of the Convert.ToInt32( String ) and ' Convert.ToInt32( String, IFormatProvider ) methods. Imports System.Globalization Module Example Dim format As String = "{0,-20}{1,-20}{2}" ' Get the exception type name; remove the namespace prefix. Function GetExceptionType(ByVal ex As Exception) As String Dim exceptionType As String = ex.GetType().ToString() Return exceptionType.Substring( _ exceptionType.LastIndexOf("."c) + 1) End Function Sub ConvertToInt32(ByVal outputBlock As System.Windows.Controls.TextBlock, ByVal numericStr As String, _ ByVal provider As IFormatProvider) Dim defaultValue As Object Dim providerValue As Object ' Convert numericStr to Int32 without a format provider. Try defaultValue = Convert.ToInt32(numericStr) Catch ex As Exception defaultValue = GetExceptionType(ex) End Try ' Convert numericStr to Int32 with a format provider. Try providerValue = Convert.ToInt32(numericStr, provider) Catch ex As Exception providerValue = GetExceptionType(ex) End Try outputBlock.Text &= String.Format(format, numericStr, _ defaultValue, providerValue) & vbCrLf End Sub Public Sub Demo(ByVal outputBlock As System.Windows.Controls.TextBlock) ' Create a NumberFormatInfo object and set several of its ' properties that apply to numbers. Dim provider As NumberFormatInfo = New NumberFormatInfo() ' These properties affect the conversion. provider.NegativeSign = "neg " provider.PositiveSign = "pos " ' These properties do not affect the conversion. ' The input string cannot have decimal and group separators. provider.NumberDecimalSeparator = "." provider.NumberGroupSeparator = "," provider.NumberGroupSizes = New Integer() {3} provider.NumberNegativePattern = 0 outputBlock.Text &= String.Format("This example of" & vbCrLf & _ " Convert.ToInt32( String ) and " & vbCrLf & _ " Convert.ToInt32( String, IFormatProvider ) " & _ vbCrLf & "generates the following output. It " & _ "converts several strings to " & vbCrLf & "Integer " & _ "values, using default formatting " & _ "or a NumberFormatInfo object." & vbCrLf) & vbCrLf outputBlock.Text &= String.Format(format, "String to convert", _ "Default/exception", "Provider/exception") & vbCrLf outputBlock.Text &= String.Format(format, "-----------------", _ "-----------------", "------------------") & vbCrLf ' Convert strings, with and without an IFormatProvider. ConvertToInt32(outputBlock, "123456789", provider) ConvertToInt32(outputBlock, "+123456789", provider) ConvertToInt32(outputBlock, "pos 123456789", provider) ConvertToInt32(outputBlock, "-123456789", provider) ConvertToInt32(outputBlock, "neg 123456789", provider) ConvertToInt32(outputBlock, "123456789.", provider) ConvertToInt32(outputBlock, "123,456,789", provider) ConvertToInt32(outputBlock, "(123456789)", provider) ConvertToInt32(outputBlock, "2147483648", provider) ConvertToInt32(outputBlock, "-2147483649", provider) End Sub End Module ' This example of ' Convert.ToInt32( String ) and ' Convert.ToInt32( String, IFormatProvider ) ' generates the following output. It converts several strings to ' Integer values, using default formatting or a NumberFormatInfo object. ' ' String to convert Default/exception Provider/exception ' ----------------- ----------------- ------------------ ' 123456789 123456789 123456789 ' +123456789 123456789 FormatException ' pos 123456789 FormatException 123456789 ' -123456789 -123456789 FormatException ' neg 123456789 FormatException -123456789 ' 123456789. FormatException FormatException ' 123,456,789 FormatException FormatException ' (123456789) FormatException FormatException ' 2147483648 OverflowException OverflowException ' -2147483649 OverflowException FormatException