Code:
/ DotNET / DotNET / 8.0 / untmp / WIN_WINDOWS / lh_tools_devdiv_wpf / Windows / wcp / Framework / System / Windows / Documents / ZoomPercentageConverter.cs / 1 / ZoomPercentageConverter.cs
//---------------------------------------------------------------------------- // //// Copyright (C) Microsoft Corporation. All rights reserved. // // // // Description: Contains the ZoomPercentageConverter: TypeConverter for the // ZoomPercentage property of DocumentViewer. // // History: // 01/11/2005 - [....] - Created // //--------------------------------------------------------------------------- // Used to support the warnings disabled below #pragma warning disable 1634, 1691 using System; using System.Globalization; using System.Windows.Data; namespace System.Windows.Documents { ////// ValueConverter for DocumentViewer's ZoomPercentage property /// public sealed class ZoomPercentageConverter : IValueConverter { //----------------------------------------------------- // // Constructors // //----------------------------------------------------- ////// Instantiates a new instance of a ZoomPercentageConverter /// public ZoomPercentageConverter() {} //------------------------------------------------------ // // Public Methods // //----------------------------------------------------- ////// Convert a value. Called when moving a value from ZoomPercentage to UI. /// /// value produced by the ZoomPercentage property /// target type /// converter parameter /// culture information ////// Converted value. /// /// System.Windows.DependencyProperty.UnsetValue may be returned to indicate that /// the converter produced no value and that the fallback (if available) /// or default value should be used instead. /// /// Binding.DoNothing may be returned to indicate that the binding /// should not transfer the value or use the fallback or default value. /// ////// The data binding engine does not catch exceptions thrown by a user-supplied /// converter. Thus any exception thrown by Convert, or thrown by methods /// it calls and not caught by the Convert, will be treated as a runtime error /// (i.e. a crash). Convert should handle anticipated problems by returning /// DependencyProperty.UnsetValue. /// public object Convert(object value, Type targetType, object parameter, CultureInfo culture) { // Check if the targetType has been defined correctly. if (targetType == null) { return DependencyProperty.UnsetValue; } // Ensure that the value given is a double. if (value != null && value is double) { double percent = (double)value; // If string requested, format string. // If object is requested, then return a formated string. This covers cases // similar to ButtonBase.CommandParameter, etc. if ((targetType == typeof(string)) || (targetType == typeof(object))) { // Check that value is a valid double. if ((double.IsNaN(percent)) || (double.IsInfinity(percent))) { return DependencyProperty.UnsetValue; } else { // Ensure output string is formatted to current globalization standards. return String.Format(CultureInfo.CurrentCulture, SR.Get(SRID.ZoomPercentageConverterStringFormat), percent); } } // If double requested, return direct value. else if (targetType == typeof(double)) { return percent; } } return DependencyProperty.UnsetValue; } ////// Convert back a value. Called when moving a value into a ZoomPercentage. /// /// value, as produced by target /// target type /// converter parameter /// culture information ////// Converted back value. /// /// Binding.DoNothing may be returned to indicate that no value /// should be set on the source property. /// /// System.Windows.DependencyProperty.UnsetValue may be returned to indicate /// that the converter is unable to provide a value for the source /// property, and no value will be set to it. /// ////// The data binding engine does not catch exceptions thrown by a user-supplied /// converter. Thus any exception thrown by ConvertBack, or thrown by methods /// it calls and not caught by the ConvertBack, will be treated as a runtime error /// (i.e. a crash). ConvertBack should handle anticipated problems by returning /// DependencyProperty.UnsetValue. /// public object ConvertBack(object value, Type targetType, object parameter, CultureInfo culture) { if ((targetType == typeof(double)) && (value != null)) { double zoomValue = 0.0; bool isValidArg = false; // If value an int, then cast if (value is int) { zoomValue = (double)(int)value; isValidArg = true; } // If value is a double, then cast else if (value is double) { zoomValue = (double)value; isValidArg = true; } // If value is a string, then parse else if (value is string) { try { // Remove whitespace on either end of the string. string zoomString = (string)value; if ((culture != null) && !String.IsNullOrEmpty(zoomString)) { zoomString = ((string)value).Trim(); // If this is not a neutral culture attempt to remove the percent symbol. if ((!culture.IsNeutralCulture) && (zoomString.Length > 0) && (culture.NumberFormat != null)) { // This will strip the percent sign (if it exists) depending on the culture information. switch (culture.NumberFormat.PercentPositivePattern) { case 0: // n % case 1: // n% // Remove the last character if it is a percent sign if (zoomString.Length - 1 == zoomString.LastIndexOf( culture.NumberFormat.PercentSymbol, StringComparison.CurrentCultureIgnoreCase)) { zoomString = zoomString.Substring(0, zoomString.Length - 1); } break; case 2: // %n // Remove the first character if it is a percent sign. if (0 == zoomString.IndexOf( culture.NumberFormat.PercentSymbol, StringComparison.CurrentCultureIgnoreCase)) { zoomString = zoomString.Substring(1); } break; } } // If this conversion throws then the string wasn't a valid zoom value. zoomValue = System.Convert.ToDouble(zoomString, culture); isValidArg = true; } } // Allow empty catch statements. #pragma warning disable 56502 // Catch only the expected parse exceptions catch (ArgumentOutOfRangeException) { } catch (ArgumentNullException) { } catch (FormatException) { } catch (OverflowException) { } // Disallow empty catch statements. #pragma warning restore 56502 } // Argument wasn't a valid percent, set error value. if (!isValidArg) { return DependencyProperty.UnsetValue; } return zoomValue; } // Requested type is not supported. else { return DependencyProperty.UnsetValue; } } } } // File provided for Reference Use Only by Microsoft Corporation (c) 2007. // Copyright (c) Microsoft Corporation. All rights reserved.
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