# ISheetSymbol interface

The `ISheetSymbol` interface is a sheet symbol interface to an existing sheet symbol object on the schematic. Sheet symbols represent other schematic sheets (often referred to as a child sheet). The link between a sheet symbol and other schematic sheets is the FileName attribute, which must be the same as the name of the child sheet.

```csharp
public interface ISheetSymbol : IDMObject
```

**Namespace:** EDP · **Assembly:** Altium.SDK.Interfaces

**Inherits:** [IDMObject](https://altiumdeveloper.github.io/ad-sdk-docs/reference/edp/IDMObject.md)

## Remarks

An equivalent Sheet Symbol object representation is the [`ISch_SheetSymbol`](https://altiumdeveloper.github.io/ad-sdk-docs/reference/sch/ISch_SheetSymbol.md) class in Sch API Reference.

## Methods

| Method | Returns | Description |
| --- | --- | --- |
| [DM_CalculatedDesignator](#dm_calculateddesignator) | `string` | This method returns the calculated designator string which contains the hierarchical path and the logical designator strings. |
| [DM_ChildSheet](#dm_childsheet) | [IDocument](https://altiumdeveloper.github.io/ad-sdk-docs/reference/edp/IDocument.md) | Returns the indexed child sheet associated with this sheet symbol object. |
| [DM_ChildSheetCount](#dm_childsheetcount) | `int` | Returns the number of child sheets associated with this sheet symbol object. |
| [DM_DesignItemID](#dm_designitemid) | `string` |  |
| [DM_ItemGUID](#dm_itemguid) | `string` |  |
| [DM_LogicalDesignator](#dm_logicaldesignator) | `string` | Returns the logical designator of this sheet symbol. |
| [DM_PhysicalDesignator](#dm_physicaldesignator) | `string` | Returns the designator of this sheet symbol. |
| [DM_RevisionGUID](#dm_revisionguid) | `string` |  |
| [DM_SheetEntries](#dm_sheetentries) | [INetItem](https://altiumdeveloper.github.io/ad-sdk-docs/reference/edp/INetItem.md) | Returns the number of sheet entries that are associated with this sheet symbol. |
| [DM_SheetEntryCount](#dm_sheetentrycount) | `int` | Returns the number of sheet entries associated with this sheet symbol object. |
| [DM_SheetSymbolFileName](#dm_sheetsymbolfilename) | `string` | Returns the filename which is a link between this sheet symbol object and the other schematic sheet. |
| [DM_SourceLibraryName](#dm_sourcelibraryname) | `string` |  |
| [DM_UniqueId](#dm_uniqueid) | `string` | Returns the unique ID of this sheet symbol object. |
| [DM_VaultGUID](#dm_vaultguid) | `string` |  |

### DM_CalculatedDesignator

This method returns the calculated designator string which contains the hierarchical path and the logical designator strings. Only when a project is compiled and up to date, designators of sheet symbols are calculated based on the physical documents they are on.

```csharp
string DM_CalculatedDesignator();
```

**Returns:** `string`

### DM_ChildSheet

Returns the indexed child sheet associated with this sheet symbol object. Use in conjunction with the [`DM_ChildSheetCount`](#dm_childsheetcount) method.

```csharp
IDocument DM_ChildSheet(int argIndex);
```

| Parameter | Type | Passing |
| --- | --- | --- |
| `argIndex` | `int` | value |

**Returns:** [IDocument](https://altiumdeveloper.github.io/ad-sdk-docs/reference/edp/IDocument.md)

Extension method of `ISheetSymbolHelper` (`using EDP;`).

### DM_ChildSheetCount

Returns the number of child sheets associated with this sheet symbol object.

```csharp
int DM_ChildSheetCount();
```

**Returns:** `int`

### DM_DesignItemID

*No description yet.*

```csharp
string DM_DesignItemID();
```

**Returns:** `string`

### DM_ItemGUID

*No description yet.*

```csharp
string DM_ItemGUID();
```

**Returns:** `string`

### DM_LogicalDesignator

Returns the logical designator of this sheet symbol. A logical designator is not unique, since logical designators are used in multi channel designs.

```csharp
string DM_LogicalDesignator();
```

**Returns:** `string`

### DM_PhysicalDesignator

Returns the designator of this sheet symbol. Every physical designator is unique.

```csharp
string DM_PhysicalDesignator();
```

**Returns:** `string`

### DM_RevisionGUID

*No description yet.*

```csharp
string DM_RevisionGUID();
```

**Returns:** `string`

### DM_SheetEntries

Returns the number of sheet entries that are associated with this sheet symbol. Since a sheet entry is of a [`INetItem`](https://altiumdeveloper.github.io/ad-sdk-docs/reference/edp/INetItem.md) type, thus a [`INetItem`](https://altiumdeveloper.github.io/ad-sdk-docs/reference/edp/INetItem.md) interface is returned.

```csharp
INetItem DM_SheetEntries(int argIndex);
```

| Parameter | Type | Passing |
| --- | --- | --- |
| `argIndex` | `int` | value |

**Returns:** [INetItem](https://altiumdeveloper.github.io/ad-sdk-docs/reference/edp/INetItem.md)

Extension method of `ISheetSymbolHelper` (`using EDP;`).

### DM_SheetEntryCount

Returns the number of sheet entries associated with this sheet symbol object.

```csharp
int DM_SheetEntryCount();
```

**Returns:** `int`

### DM_SheetSymbolFileName

Returns the filename which is a link between this sheet symbol object and the other schematic sheet.

```csharp
string DM_SheetSymbolFileName();
```

**Returns:** `string`

### DM_SourceLibraryName

*No description yet.*

```csharp
string DM_SourceLibraryName();
```

**Returns:** `string`

### DM_UniqueId

Returns the unique ID of this sheet symbol object.

```csharp
string DM_UniqueId();
```

**Returns:** `string`

### DM_VaultGUID

*No description yet.*

```csharp
string DM_VaultGUID();
```

**Returns:** `string`

## Inherited members

- From [IDMObject](https://altiumdeveloper.github.io/ad-sdk-docs/reference/edp/IDMObject.md): [DM_CalculateParameterValue](https://altiumdeveloper.github.io/ad-sdk-docs/reference/edp/IDMObject.md#dm_calculateparametervalue), [DM_CurrentSheetInstanceNumber](https://altiumdeveloper.github.io/ad-sdk-docs/reference/edp/IDMObject.md#dm_currentsheetinstancenumber), [DM_FullCrossProbeString](https://altiumdeveloper.github.io/ad-sdk-docs/reference/edp/IDMObject.md#dm_fullcrossprobestring), [DM_GeneralField](https://altiumdeveloper.github.io/ad-sdk-docs/reference/edp/IDMObject.md#dm_generalfield), [DM_GetVCSProject](https://altiumdeveloper.github.io/ad-sdk-docs/reference/edp/IDMObject.md#dm_getvcsproject), [DM_ImageIndex](https://altiumdeveloper.github.io/ad-sdk-docs/reference/edp/IDMObject.md#dm_imageindex), [DM_IsFormulaString](https://altiumdeveloper.github.io/ad-sdk-docs/reference/edp/IDMObject.md#dm_isformulastring), [DM_IsInferredObject](https://altiumdeveloper.github.io/ad-sdk-docs/reference/edp/IDMObject.md#dm_isinferredobject), [DM_LocationString](https://altiumdeveloper.github.io/ad-sdk-docs/reference/edp/IDMObject.md#dm_locationstring), [DM_LocationX](https://altiumdeveloper.github.io/ad-sdk-docs/reference/edp/IDMObject.md#dm_locationx), [DM_LocationY](https://altiumdeveloper.github.io/ad-sdk-docs/reference/edp/IDMObject.md#dm_locationy), [DM_LongDescriptorString](https://altiumdeveloper.github.io/ad-sdk-docs/reference/edp/IDMObject.md#dm_longdescriptorstring), [DM_NetIndex_Flat](https://altiumdeveloper.github.io/ad-sdk-docs/reference/edp/IDMObject.md#dm_netindex_flat), [DM_NetIndex_Sheet](https://altiumdeveloper.github.io/ad-sdk-docs/reference/edp/IDMObject.md#dm_netindex_sheet), [DM_NetIndex_SubNet](https://altiumdeveloper.github.io/ad-sdk-docs/reference/edp/IDMObject.md#dm_netindex_subnet), [DM_ObjectKindString](https://altiumdeveloper.github.io/ad-sdk-docs/reference/edp/IDMObject.md#dm_objectkindstring), [DM_ObjectKindStringForCrossProbe](https://altiumdeveloper.github.io/ad-sdk-docs/reference/edp/IDMObject.md#dm_objectkindstringforcrossprobe), [DM_OwnerDocument](https://altiumdeveloper.github.io/ad-sdk-docs/reference/edp/IDMObject.md#dm_ownerdocument), [DM_OwnerDocumentFullPath](https://altiumdeveloper.github.io/ad-sdk-docs/reference/edp/IDMObject.md#dm_ownerdocumentfullpath), [DM_OwnerDocumentName](https://altiumdeveloper.github.io/ad-sdk-docs/reference/edp/IDMObject.md#dm_ownerdocumentname), [DM_ParameterCount](https://altiumdeveloper.github.io/ad-sdk-docs/reference/edp/IDMObject.md#dm_parametercount), [DM_Parameters](https://altiumdeveloper.github.io/ad-sdk-docs/reference/edp/IDMObject.md#dm_parameters), [DM_PcbHandle](https://altiumdeveloper.github.io/ad-sdk-docs/reference/edp/IDMObject.md#dm_pcbhandle), [DM_PCBObjectHandle](https://altiumdeveloper.github.io/ad-sdk-docs/reference/edp/IDMObject.md#dm_pcbobjecthandle), [DM_PCBObjectInterface](https://altiumdeveloper.github.io/ad-sdk-docs/reference/edp/IDMObject.md#dm_pcbobjectinterface), [DM_PrimaryCrossProbeString](https://altiumdeveloper.github.io/ad-sdk-docs/reference/edp/IDMObject.md#dm_primarycrossprobestring), [DM_SchHandle](https://altiumdeveloper.github.io/ad-sdk-docs/reference/edp/IDMObject.md#dm_schhandle), [DM_SCHObjectHandle](https://altiumdeveloper.github.io/ad-sdk-docs/reference/edp/IDMObject.md#dm_schobjecthandle), [DM_SCHObjectInterface](https://altiumdeveloper.github.io/ad-sdk-docs/reference/edp/IDMObject.md#dm_schobjectinterface), [DM_SecondaryCrossProbeString](https://altiumdeveloper.github.io/ad-sdk-docs/reference/edp/IDMObject.md#dm_secondarycrossprobestring), [DM_SetVCSProject](https://altiumdeveloper.github.io/ad-sdk-docs/reference/edp/IDMObject.md#dm_setvcsproject), [DM_SheetIndex_Logical](https://altiumdeveloper.github.io/ad-sdk-docs/reference/edp/IDMObject.md#dm_sheetindex_logical), [DM_SheetIndex_Physical](https://altiumdeveloper.github.io/ad-sdk-docs/reference/edp/IDMObject.md#dm_sheetindex_physical), [DM_ShortDescriptorString](https://altiumdeveloper.github.io/ad-sdk-docs/reference/edp/IDMObject.md#dm_shortdescriptorstring), [DM_ValidForNavigation](https://altiumdeveloper.github.io/ad-sdk-docs/reference/edp/IDMObject.md#dm_validfornavigation), [DM_VHDLEntity](https://altiumdeveloper.github.io/ad-sdk-docs/reference/edp/IDMObject.md#dm_vhdlentity)

## Returned by

[IBlanket.DM_SheetSymbols](https://altiumdeveloper.github.io/ad-sdk-docs/reference/edp/IBlanket.md#dm_sheetsymbols), [IDocument.DM_HarnessConnectors](https://altiumdeveloper.github.io/ad-sdk-docs/reference/edp/IDocument.md#dm_harnessconnectors), [IDocument.DM_ParentSheetSymbols](https://altiumdeveloper.github.io/ad-sdk-docs/reference/edp/IDocument.md#dm_parentsheetsymbols), [IDocument.DM_SheetSymbols](https://altiumdeveloper.github.io/ad-sdk-docs/reference/edp/IDocument.md#dm_sheetsymbols), [IInstance.DM_SheetSymbol](https://altiumdeveloper.github.io/ad-sdk-docs/reference/edp/IInstance.md#dm_sheetsymbol), [INetItem.DM_SheetSymbol](https://altiumdeveloper.github.io/ad-sdk-docs/reference/edp/INetItem.md#dm_sheetsymbol)