OpacityConverter.cs source code in C# .NET

Source code for the .NET framework in C#

                        
Code:

                         / DotNET / DotNET / 8.0 / untmp / whidbey / REDBITS / ndp / fx / src / WinForms / Managed / System / WinForms / OpacityConverter.cs / 1 / OpacityConverter.cs
                        

                        
                            //------------------------------------------------------------------------------ 
// 
//     Copyright (c) Microsoft Corporation.  All rights reserved.
// 
//----------------------------------------------------------------------------- 

/* 
 */ 
namespace System.Windows.Forms {
    using System.Runtime.Serialization.Formatters; 
    using System.Runtime.Remoting;
    using System.Runtime.InteropServices;

    using Microsoft.Win32; 
    using System.Collections;
    using System.ComponentModel; 
    using System.Diagnostics; 
    using System.Globalization;
    using System.Reflection; 

    /// 
    /// 
    ///      OpacityConverter is a class that can be used to convert 
    ///      opacity values from one data type to another.  Access this
    ///      class through the TypeDescriptor. 
    ///  
    public class OpacityConverter : TypeConverter {
 
        /// 
        /// 
        ///      Determines if this converter can convert an object in the given source
        ///      type to the native type of the converter. 
        /// 
        public override bool CanConvertFrom(ITypeDescriptorContext context, Type sourceType) { 
            if (sourceType == typeof(string)) { 
                return true;
            } 
            return base.CanConvertFrom(context, sourceType);
        }

        ///  
        /// 
        ///      Converts the given object to the converter's native type. 
        ///  
        public override object ConvertFrom(ITypeDescriptorContext context, CultureInfo culture, object value) {
            if (value is string) { 

                string text = ((string)value).Replace('%', ' ').Trim();
                double val = Double.Parse(text, CultureInfo.CurrentCulture);
                int indexOfPercent = ((string)value).IndexOf("%"); 
                if (indexOfPercent > 0 && (val >= 0.0 && val <= 1.0)) {
                    val /= 100.0; 
                    text = val.ToString(CultureInfo.CurrentCulture); 
                }
                double percent = 1.0; 

                try {
                    percent = (double)TypeDescriptor.GetConverter(typeof(double)).ConvertFrom(context, culture, text);
 
                    // assume they meant a percentage if it is > 1.0, else
                    // they actually typed the correct double... 
                    // 
                    if (percent > 1.0) {
                        percent /= 100.0; 
                    }
                }
                catch (FormatException e) {
                    throw new FormatException(SR.GetString(SR.InvalidBoundArgument, 
                                                                    "Opacity",
                                                                    text, 
                                                                    "0%", 
                                                                    "100%"), e);
                } 

                // Now check to see if it is within our bounds.
                //
                if (percent < 0.0 || percent > 1.0) { 
                    throw new FormatException(SR.GetString(SR.InvalidBoundArgument,
                                                                    "Opacity", 
                                                                    text, 
                                                                    "0%",
                                                                    "100%")); 
                }

                return percent;
            } 

            return base.ConvertFrom(context, culture, value); 
        } 

        ///  
        /// 
        ///      Converts the given object to another type.  The most common types to convert
        ///      are to and from a string object.  The default implementation will make a call
        ///      to ToString on the object if the object is valid and if the destination 
        ///      type is string.  If this cannot convert to the desitnation type, this will
        ///      throw a NotSupportedException. 
        ///  
        public override object ConvertTo(ITypeDescriptorContext context, CultureInfo culture, object value, Type destinationType) {
            if (destinationType == null) { 
                throw new ArgumentNullException("destinationType");
            }

            if (destinationType == typeof(string)) { 
                double val = (double)value;
                int perc = (int)(val * 100.0); 
                return perc.ToString(CultureInfo.CurrentCulture) + "%"; 
            }
 
            return base.ConvertTo(context, culture, value, destinationType);
        }
    }
} 


// File provided for Reference Use Only by Microsoft Corporation (c) 2007.
// Copyright (c) Microsoft Corporation. All rights reserved.

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