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IData Interface
IData Interface
- GetRecordCount
- GetFieldCount
- GetFieldAt
- GetDoubleAt
- GetLongAt
- GetStringAt
- GetFieldType
- GetFieldDescription
IData manages a data set. A data set is an array of records similar to a
database table. Each record consists of fixed number of fields of different
type.
In this release the only place where IData is involved is the IntersectObject
method of ILineMetr interface.
See also
Cannon sample,
Interface List
HRESULT GetRecordCount(int *count)
Parameters
count- [out] reference to an integer
variable which will be set to number of records in the record set
Returns
- S_OK in case of
success.
-
- Remarks:
The method returns the number record in the record set.
HRESULT GetFieldCount(int *count)
Parameters
count- [out] reference to an integer
variable which will be set to number of fields in each record of the set.
Return Values
- S_OK in case of
success.
- Remarks:
-
- This method returns number of fields in each record of the record
set. This method along with the GetFieldDescription
and GetFieldType methods allows discovering
structure of the data table at runtime.
HRESULT GetFieldAt(int index, int field, VARIANT
*data)
Parameters
index - [in] index of a record in
the record set.
field - [in] index of the field in the record to
be retrieved
data - [out] returned value of the field. See
remarks.
Returns
S_OK in case of
success.
DISP_E_BADINDEX if index or field are
out of range.
Remarks:
This method will return value of field-th field in index-th
record. Type of data is described by vt member of the data
parameter.
HRESULT GetDoubleAt(int index, int field, double *data)
Parameters
index - [in] index of a record in
the record set.
field - [in] index of the field in the record to
be retrieved
data - [out] returned value of the field.
Returns
S_OK in case of
success.
DISP_E_BADINDEX if index or field are
out of range.
DISP_E_PARAMNOTOPTIONAL if field does not have
double or single type
Remarks:
This a shortcut for GetFieldAt method above/
This method will return value of field-th field in index-th
record. The caller has to make sure that the field has double type. Types of
each field in the table are described by the documentation for every particular
usage. It ca also be retrieved at runtime using GetFieldType
and GetFieldDescription.
HRESULT GetLongAt(int index, int field, long *data)
Parameters
index - [in] index of a record in
the record set.
field - [in] index of the field in the record to
be retrieved
data - [out] returned value of the field.
Returns
S_OK in case of
success.
DISP_E_BADINDEX if index or field are
out of range.
DISP_E_PARAMNOTOPTIONAL if field does not have
integral type.
Remarks:
This a shortcut for GetFieldAt method above/
This method will return value of field-th field in index-th
record. The caller has to make sure that the field has integer type.
Types of each field in the table are described by the documentation for every
particular usage. It ca also be retrieved at runtime using GetFieldType
and GetFieldDescription.
HRESULT GetStringAt(int index, int field, BSTR *string)
Parameters
index - [in] index of a record in
the record set.
field - [in] index of the field in the record to
be retrieved
string - [out] returned value of the field.
Returns
S_OK in case of
success.
DISP_E_BADINDEX if index or field are
out of range.
DISP_E_PARAMNOTOPTIONAL if field does not have
string type.
Remarks:
This a shortcut for GetFieldAt method above/
This method will return value of field-th field in index-th
record. The caller has to make sure that the field has integer type.
Types of each field in the table are described by the documentation for every
particular case. It ca also be retrieved at runtime using GetFieldType
and GetFieldDescription.
HRESULT GetFieldType(int field, EDataType* type)
Parameters
index - [in] index of a record in
the record set.
field - [in] index of the field in the record to
be retrieved
type - [out] returned value, member of EDataType enumeration
describing the type of the field.
Returns
S_OK in case of
success.
Remarks:
This method along with the GetFieldCount
and GetFieldDescription methods allows discovering
structure of the data table at runtime.
HRESULT GetFieldDescription(int field, BSTR *descript)
Parameters
field - [in] index of the field in the table
descript - [out] returned description string
Returns
S_OK in case of
success.
Remarks:
The method returns a short description of data stored in the field of the data
table.
This method along with the GetFieldCount
and GetFieldType methods allows discovering
structure of the data table at runtime.
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