/// <summary>
/// Gets the value associated with a key and converts it into T or throws.
/// </summary>
/// <typeparam name="T">Type to convert value into.</typeparam>
/// <param name="dictionary">Dictionary to get value from.</param>
/// <param name="key">The key associated with the desired value.</param>
/// <returns>The value associated with the key converted into T.</returns>
/// <exception cref="KeyNotFoundException">Thrown when the key cannot be found in the dictionary.</exception>
/// <exception cref="NotSupportedException">Thrown when a conversion from string to T is impossible.</exception>
/// <exception cref="ArgumentException">Thrown when the value associated with the key in the dictionary is null or empty.</exception>
public static T GetOrThrow<T>(this IDictionary<string, string> dictionary, string key)
{
var value = dictionary[key];
if (string.IsNullOrEmpty(value))
{
throw new ArgumentException($"Value associated with key {key} in the dictionary is null or empty.");
}
return ConfigurationUtility.ConvertFromString<T>(value);
}
public async Task <T> GetOrThrowAsync <T>(string key)
{
if (string.IsNullOrEmpty(key))
{
throw new ArgumentException($"{nameof(key)} cannot be null or empty!", nameof(key));
}
var value = await Get(key);
if (string.IsNullOrEmpty(value))
{
throw new ConfigurationNullOrEmptyException(key);
}
return(ConfigurationUtility.ConvertFromString <T>(value));
}
/// <summary>
/// Gets the value associated with a key and converts it into T or returns a specified default.
/// </summary>
/// <typeparam name="T">Type to convert value into.</typeparam>
/// <param name="dictionary">Dictionary to get value from.</param>
/// <param name="key">The key associated with the desired value.</param>
/// <param name="defaultValue">The default value to return if the key cannot be found.</param>
/// <returns>The value associated with key converted into T or null.</returns>
/// <exception cref="NotSupportedException">Thrown when a conversion from string to T is impossible.</exception>
public static T GetOrDefault<T>(this IDictionary<string, string> dictionary, string key, T defaultValue = default(T))
{
string valueString;
return dictionary.TryGetValue(key, out valueString) ? ConfigurationUtility.ConvertFromString<T>(valueString) : defaultValue;
}