Condividi tramite

  • Articolo

Convert.ToBoolean Method (String, IFormatProvider)

Microsoft Silverlight will reach end of support after October 2021. Learn more.

Converts the specified String representation of a logical value to its Boolean equivalent using the specified culture-specific formatting information.

Namespace:  System
Assembly:  mscorlib (in mscorlib.dll)

Syntax

'Declaration
Public Shared Function ToBoolean ( _
    value As String, _
    provider As IFormatProvider _
) As Boolean

public static bool ToBoolean(
    string value,
    IFormatProvider provider
)

Parameters

Return Value

Type: System.Boolean
true if value equals TrueString, or false if value equals FalseString or nulla null reference (Nothing in Visual Basic).

Exceptions

Exception Condition
FormatException

value is not equal to TrueString or FalseString.

Remarks

provider is ignored; it does not participate in this operation.

If you prefer not to handle an exception if the conversion fails, you can call the Boolean.TryParse method instead. It returns a Boolean value that indicates whether the conversion succeeded or failed.

Examples

The following code sample illustrates the use of ToBoolean, taking a String parameter.

Public Sub ConvertStringBoolean(ByVal stringVal As String)

   Dim boolVal As Boolean = False

   Try
      boolVal = System.Convert.ToBoolean(stringVal)
      If boolVal Then
         outputBlock.Text &= String.Format( _
             "String is equal to System.Boolean.TrueString.") & vbCrLf
      Else
         outputBlock.Text &= String.Format( _
             "String is equal to System.Boolean.FalseString.") & vbCrLf
      End If
   Catch exception As System.FormatException
      outputBlock.Text &= String.Format( _
          "The string must equal System.Boolean.TrueString " + _
          "or System.Boolean.FalseString.") & vbCrLf
   End Try

   ' A conversion from bool to string will always succeed.
   stringVal = System.Convert.ToString(boolVal)
   outputBlock.Text &= String.Format("{0} as a String is {1}", _
                             boolVal, stringVal) & vbCrLf
End Sub

public void ConvertStringBoolean(string stringVal)
{
   bool boolVal = false;

   try
   {
      boolVal = System.Convert.ToBoolean(stringVal);
      if (boolVal)
      {
         outputBlock.Text += String.Format(
            "String was equal to System.Boolean.TrueString.") + "\n";
      }
      else
      {
         outputBlock.Text += String.Format(
            "String was equal to System.Boolean.FalseString.") + "\n";
      }
   }
   catch (System.FormatException)
   {
      outputBlock.Text += String.Format(
         "The string must equal System.Boolean.TrueString " +
         "or System.Boolean.FalseString.") + "\n";
   }

   // A conversion from bool to string will always succeed.
   stringVal = System.Convert.ToString(boolVal);
   outputBlock.Text += String.Format("{0} as a string is {1}",
      boolVal, stringVal) + "\n";
}

Version Information

Silverlight

Supported in: 5, 4, 3

Silverlight for Windows Phone

Supported in: Windows Phone OS 7.1, Windows Phone OS 7.0

XNA Framework

Supported in: Xbox 360, Windows Phone OS 7.0

Platforms

For a list of the operating systems and browsers that are supported by Silverlight, see Supported Operating Systems and Browsers.