## ExtendedAttributeDefinition class

Represents an extended attribute definition associated with a project.

```csharp
public class ExtendedAttributeDefinition
```

## Properties

| Name | Description |
| --- | --- |
| [Alias](../../aspose.tasks/extendedattributedefinition/alias/) { get; set; } | Gets or sets the alias of a custom field. |
| [AppendNewValues](../../aspose.tasks/extendedattributedefinition/appendnewvalues/) { get; set; } | Gets or sets a value indicating whether new values added to a project are automatically added to the list. |
| [AutoRollDown](../../aspose.tasks/extendedattributedefinition/autorolldown/) { get; set; } | Gets or sets a value indicating whether an automatic roll down to assignments is enabled. |
| [CalculationType](../../aspose.tasks/extendedattributedefinition/calculationtype/) { get; set; } | Gets or sets the type of calculation of the custom attribute's value. |
| [CfType](../../aspose.tasks/extendedattributedefinition/cftype/) { get; } | Gets the type of a custom field. |
| [Default](../../aspose.tasks/extendedattributedefinition/default/) { get; set; } | Gets or sets the default value in the list. |
| [DefaultGuid](../../aspose.tasks/extendedattributedefinition/defaultguid/) { get; set; } | Gets or sets the Guid of the default lookup table entry. |
| [ElementType](../../aspose.tasks/extendedattributedefinition/elementtype/) { get; set; } | Gets or sets the extended attribute is associated with a task, a resource or an assignment. |
| [FieldId](../../aspose.tasks/extendedattributedefinition/fieldid/) { get; set; } | Gets or sets corresponds to the project id of a custom field. Use string representation of a constant from [`ExtendedAttributeTask`](../extendedattributetask/) class to specify [`FieldId`](./fieldid/) property. |
| [FieldName](../../aspose.tasks/extendedattributedefinition/fieldname/) { get; } | Gets the name of a custom field. |
| [Formula](../../aspose.tasks/extendedattributedefinition/formula/) { get; set; } | Gets or sets the formula that Microsoft Project uses to populate a custom task field. |
| [GraphicalIndicator](../../aspose.tasks/extendedattributedefinition/graphicalindicator/) { get; set; } | Gets or sets a graphical indicators info associated with the extended attribute. Applicable to MPP format. |
| [Guid](../../aspose.tasks/extendedattributedefinition/guid/) { get; set; } | Gets or sets the Guid of a custom field. |
| [LookupUid](../../aspose.tasks/extendedattributedefinition/lookupuid/) { get; } | Gets a Guid of the lookup table associated with a custom field. |
| [MaxMultiValues](../../aspose.tasks/extendedattributedefinition/maxmultivalues/) { get; set; } | Gets or sets the maximum number of values you can set in a pick list. |
| [ParentProject](../../aspose.tasks/extendedattributedefinition/parentproject/) { get; } | Gets the parent project for the `ExtendedAttributeDefinition` instance. |
| [PhoneticsAlias](../../aspose.tasks/extendedattributedefinition/phoneticsalias/) { get; set; } | Gets or sets the phonetic pronunciation of the alias of a custom field. |
| [RestrictValues](../../aspose.tasks/extendedattributedefinition/restrictvalues/) { get; set; } | Gets or sets a value indicating whether the custom field values are restricted to values in the [`ValueList`](./valuelist/). |
| [RollupType](../../aspose.tasks/extendedattributedefinition/rolluptype/) { get; set; } | Gets or sets the way rollups are calculated. |
| [SecondaryGuid](../../aspose.tasks/extendedattributedefinition/secondaryguid/) { get; set; } | Gets or sets the secondary guid of extended attribute. |
| [SecondaryPid](../../aspose.tasks/extendedattributedefinition/secondarypid/) { get; set; } | Gets or sets the secondary PID of a custom field. |
| [SummaryRowsCalculationType](../../aspose.tasks/extendedattributedefinition/summaryrowscalculationtype/) { get; set; } | Gets or sets the type of calculation of the custom attribute's value for summary rows. |
| [UserDef](../../aspose.tasks/extendedattributedefinition/userdef/) { get; set; } | Gets or sets a value indicating whether a custom field is user defined. |
| [ValueList](../../aspose.tasks/extendedattributedefinition/valuelist/) { get; } | Gets the List<Value> ValueList. |
| [ValuelistSortOrder](../../aspose.tasks/extendedattributedefinition/valuelistsortorder/) { get; set; } | Gets or sets the way value lists are sorted. Values are: 0=Descending, 1=Ascending. |

## Methods

| Name | Description |
| --- | --- |
| static [CreateLookupResourceDefinition](../../aspose.tasks/extendedattributedefinition/createlookupresourcedefinition/#createlookupresourcedefinition_1)(ExtendedAttributeResource, string) | Factory method which creates an extended attribute definition with lookup. It has [`CalculationType`](./calculationtype/) equals to Lookup and can be used in Resources only. You are required to specify *fieldId* and *alias* when call this method. The field type is inferred from field id. |
| static [CreateLookupResourceDefinition](../../aspose.tasks/extendedattributedefinition/createlookupresourcedefinition/#createlookupresourcedefinition)(CustomFieldType, ExtendedAttributeResource, string) | Factory method which creates an extended attribute definition with lookup. It has [`CalculationType`](./calculationtype/) equals to Lookup and can be used in Resources only. You are required to specify *customFieldType*, *fieldId* and *alias* when call this method. |
| static [CreateLookupTaskDefinition](../../aspose.tasks/extendedattributedefinition/createlookuptaskdefinition/#createlookuptaskdefinition_1)(ExtendedAttributeTask, string) | Factory method which creates an extended attribute definition with lookup. It has [`CalculationType`](./calculationtype/) equals to Lookup and can be used in Tasks only. You are required to specify *fieldId* and *alias* when call this method. The field type is inferred from field id. |
| static [CreateLookupTaskDefinition](../../aspose.tasks/extendedattributedefinition/createlookuptaskdefinition/#createlookuptaskdefinition)(CustomFieldType, ExtendedAttributeTask, string) | Factory method which creates an extended attribute definition with lookup. It has [`CalculationType`](./calculationtype/) equals to Lookup and can be used in Tasks only. You are required to specify *customFieldType*, *fieldId* and *alias* when call this method. |
| static [CreateResourceDefinition](../../aspose.tasks/extendedattributedefinition/createresourcedefinition/#createresourcedefinition_1)(ExtendedAttributeResource, string) | Factory method which creates a simple extended attribute definition, which Microsoft Project shows as "None". It has [`CalculationType`](./calculationtype/) equals to None and can be used in Resource only. You are required to specify *fieldId* and *alias* when call this method. The field type is inferred from field id. |
| static [CreateResourceDefinition](../../aspose.tasks/extendedattributedefinition/createresourcedefinition/#createresourcedefinition)(CustomFieldType, ExtendedAttributeResource, string) | Factory method which creates a simple extended attribute definition, which Microsoft Project shows as "None". It has [`CalculationType`](./calculationtype/) equals to None and can be used in Resource only. You are required to specify *customFieldType*, *fieldId* and *alias* when call this method. |
| static [CreateTaskDefinition](../../aspose.tasks/extendedattributedefinition/createtaskdefinition/#createtaskdefinition_1)(ExtendedAttributeTask, string) | Factory method which creates a simple extended attribute definition, which Microsoft Project shows as "None". It has [`CalculationType`](./calculationtype/) equals to None and can be used in Tasks only. You are required to specify *fieldId* and *alias* when calling this method. The field type is inferred from field id. |
| static [CreateTaskDefinition](../../aspose.tasks/extendedattributedefinition/createtaskdefinition/#createtaskdefinition)(CustomFieldType, ExtendedAttributeTask, string) | Factory method which creates a simple extended attribute definition, which Microsoft Project shows as "None". It has [`CalculationType`](./calculationtype/) equals to None and can be used in Tasks only. You are required to specify *customFieldType*, *fieldId* and *alias* when calling this method. |
| [AddLookupValue](../../aspose.tasks/extendedattributedefinition/addlookupvalue/)(Value) | Adds a value to the internal lookup list. This is a preferable way for manipulations with the [`ValueList`](./valuelist/). |
| [CreateExtendedAttribute](../../aspose.tasks/extendedattributedefinition/createextendedattribute/#createextendedattribute)() | Creates a new extended attribute with the field ID which equals to this object's field ID value. |
| [CreateExtendedAttribute](../../aspose.tasks/extendedattributedefinition/createextendedattribute/#createextendedattribute_3)(bool) | Creates a new extended attribute with the field ID which equals to this object's field ID value and the specified flag value. |
| [CreateExtendedAttribute](../../aspose.tasks/extendedattributedefinition/createextendedattribute/#createextendedattribute_4)(DateTime) | Creates a new extended attribute with the field ID which equals to this object's field ID value and the specified date value. |
| [CreateExtendedAttribute](../../aspose.tasks/extendedattributedefinition/createextendedattribute/#createextendedattribute_5)(decimal) | Creates a new extended attribute with the field ID which equals to this object's field ID value and the specified numeric value. |
| [CreateExtendedAttribute](../../aspose.tasks/extendedattributedefinition/createextendedattribute/#createextendedattribute_1)(Duration) | Creates a new extended attribute with the field ID which equals to this object's field ID value and the specified duration value. |
| [CreateExtendedAttribute](../../aspose.tasks/extendedattributedefinition/createextendedattribute/#createextendedattribute_6)(string) | Creates a new extended attribute with the field ID which equals to this object's field ID value and the specified text value. |
| [CreateExtendedAttribute](../../aspose.tasks/extendedattributedefinition/createextendedattribute/#createextendedattribute_2)(Value) | Creates new extended attribute linked with specified [`Value`](../value/) item. |
| override [Equals](../../aspose.tasks/extendedattributedefinition/equals/)(object) | Returns a flag indicating whether this instance is equal to the specified object. |
| override [GetHashCode](../../aspose.tasks/extendedattributedefinition/gethashcode/)() | Returns a hash code for the instance of the `ExtendedAttributeDefinition` class. |
| [RemoveLookupValue](../../aspose.tasks/extendedattributedefinition/removelookupvalue/)(Value) | Removes a value from the internal lookup list. This is a preferable way for manipulations with the [`ValueList`](./valuelist/). |

## Examples

Shows how to use common math functions with extended attributes.

```csharp
public static void EvaluateChoose()
{
    var project = CreateTestProjectWithCustomField();

    // Set Formula
    project.ExtendedAttributes[0].Formula = "Choose(3, \"This is a\", \"right\", \"choice\")";

    // Print extended attribute value
    var task = project.RootTask.Children.GetById(1);
    Console.WriteLine(task.ExtendedAttributes[0].TextValue);
}

public static void EvaluateIsNumeric()
{
    string[] numericFormulas =
        {
            "IsNumeric('AAA')", @"IsNUmeric(1)", "IsNumeric(1<0)", "IsNumeric(\"1.1\")", "IsNumeric(Choose((2 + Sgn(2^-3)), 123, \"one two three\"))"
        };

    var project = CreateTestProjectWithCustomField();

    foreach (var numericFormula in numericFormulas)
    {
        // Set Formula
        project.ExtendedAttributes[0].Formula = numericFormula;

        // Print extended attribute value
        var task = project.RootTask.Children.GetById(1);
        Console.WriteLine(task.ExtendedAttributes[0].TextValue);
    }
}

public static void EvaluateSwitch()
{
    var project = CreateTestProjectWithCustomField();

    // Set Formula
    project.ExtendedAttributes[0].Formula = "Switch( 0 < 1, \"0 is lesser than 1\", 0 > 1, \"0 is greater than 1\")";

    // Print extended attribute value
    var task = project.RootTask.Children.GetById(1);
    Console.WriteLine(task.ExtendedAttributes[0].TextValue);
}

public static Project CreateTestProjectWithCustomField()
{
    var project = new Project();
    var definition = ExtendedAttributeDefinition.CreateTaskDefinition(CustomFieldType.Text, ExtendedAttributeTask.Text1, "Custom Field");
    project.ExtendedAttributes.Add(definition);

    var task = project.RootTask.Children.Add("Task");

    var attribute = definition.CreateExtendedAttribute();
    task.ExtendedAttributes.Add(attribute);
    return project;
}
```

### See Also

* namespace [Aspose.Tasks](../../aspose.tasks/)
* assembly [Aspose.Tasks](../../)