public void GetDefaultEmptyTest()
{
object emptyValue;
ConvertEx.ResetEmptyValues();
emptyValue = ConvertEx.GetDefaultEmptyValue <object>();
Assert.IsNull(emptyValue);
emptyValue = ConvertEx.GetDefaultEmptyValue <string>();
Assert.IsNull(emptyValue, string.Format("The value is '{0}'.", emptyValue));
emptyValue = ConvertEx.GetDefaultEmptyValue <int>();
Assert.AreEqual(int.MinValue, emptyValue);
emptyValue = ConvertEx.GetDefaultEmptyValue <char>();
Assert.AreEqual('\0', emptyValue);
emptyValue = ConvertEx.GetDefaultEmptyValue <DateTime>();
Assert.AreEqual(DateTime.MinValue, emptyValue);
emptyValue = ConvertEx.GetDefaultEmptyValue <ConvertTest>();
Assert.IsNull(emptyValue);
emptyValue = ConvertEx.GetDefaultEmptyValue <ConvertStructTest>();
Assert.AreEqual(ConvertStructTest.Empty, emptyValue);
}
/// <summary>
/// Creates an instance of BaField
/// </summary>
/// <param name="obj">The object this belongs to.</param>
/// <param name="name">Name of the field.</param>
/// <param name="fieldType">The data type for the field.</param>
/// <param name="dflt">Default value for the field. Used to determine if the field has changed. If null, it is converted to the default value for fieldType.</param>
internal BaField(BaObject obj, string name, Type fieldType, object dflt = null)
{
if (obj == null)
{
throw new ArgumentNullException(nameof(obj));
}
if (name.IsEmpty())
{
throw new ArgumentNullException(nameof(name));
}
if (fieldType == null)
{
throw new ArgumentNullException(nameof(fieldType));
}
Object = obj;
Name = name;
FieldType = fieldType;
if (dflt == null || dflt == DBNull.Value)
{
mDefaultValue = ConvertEx.GetDefaultEmptyValue(fieldType);
}
else
{
VerifyValue(dflt, "default value");
mDefaultValue = dflt;
}
}
/// <summary>
/// Changes the type of the value.
/// </summary>
/// <param name="from"></param>
/// <param name="to"></param>
/// <param name="value"></param>
/// <param name="provider"></param>
/// <returns></returns>
public object Convert(Type from, Type to, object value, IFormatProvider provider)
{
if (to == null)
{
return(null);
}
return(ConvertEx.GetDefaultEmptyValue(to));
}
/// <summary>
/// Changes the type of the value.
/// </summary>
/// <param name="value">The object to convert.</param>
/// <param name="to">The type to convert the value to.</param>
/// <param name="convertedValue">Return the value if converted.</param>
/// <returns>True if able to convert the value.</returns>
public bool TryConvert(object value, Type to, out object convertedValue)
{
if (value == null)
{
convertedValue = ConvertEx.GetDefaultEmptyValue(to);
return(true);
}
else
{
convertedValue = null;
return(false);
}
}
/// <summary>
/// Executes the command and returns the first column of the first row.
/// </summary>
/// <typeparam name="T"></typeparam>
/// <param name="cmd"></param>
/// <returns></returns>
public T ExecuteScalar <T>(DbCommand cmd)
{
var dflt = (T)ConvertEx.GetDefaultEmptyValue(typeof(T));
return(ExecuteScalar <T>(cmd, dflt));
}
/// <summary>
/// Gets an integer from an attribute or node.
/// </summary>
/// <param name="node"></param>
/// <param name="name"></param>
/// <returns></returns>
public static int GetInt(this XmlNode node, string name)
{
var dfltVal = ConvertEx.GetDefaultEmptyValue <int>();
return(GetInt(node, name));
}
/// <summary>
/// Gets a string from an attribute or node.
/// </summary>
/// <param name="node"></param>
/// <param name="name"></param>
/// <returns></returns>
public static string GetString(this XmlNode node, string name)
{
var dfltVal = ConvertEx.GetDefaultEmptyValue <string>();
return(GetString(node, name, dfltVal));
}
