Table Class Reference

The table object is used to store information from the dbf file associated with a shapefile. More...

List of all members.

Public Member Functions
bool	Calculate (string Expression, int RowIndex, out object Result, out string ErrorString)
	Calculates the the expression taking the values from the specified row of the atrribute table.
bool	Close ()
	Closes the attribute table.
bool	CreateNew (string dbfFilename)
	Creates a new attribute table.
int	EditAddField (string Name, FieldType Type, int Precision, int Width)
	Adds a field to the table. The table must be in editing mode.
bool	EditCellValue (int FieldIndex, int RowIndex, object newVal)
	Sets the value of the cell.
bool	EditClear ()
	Deletes all rows and fields from the table. Note: The table must be set to allow editing before the rows and fields can be deleted from the table.
bool	EditDeleteField (int FieldIndex, ICallback cBack)
	Deletes a field from the table.
bool	EditDeleteRow (int RowIndex)
	Deletes a row from the table.
bool	EditInsertField (Field Field, ref int FieldIndex, ICallback cBack)
	Inserts a new field into the table.
bool	EditInsertRow (ref int RowIndex)
	Inserts a new row into the table.
bool	EditReplaceField (int FieldIndex, Field NewField, ICallback cBack)
	Replaces the specified field in the table with the new field.
object	get_CellValue (int FieldIndex, int RowIndex)
	Gets the value of the specified cell in the table.
string	get_ErrorMsg (int ErrorCode)
	Retrieves the error message associated with the specified error code.
Field	get_Field (int FieldIndex)
	Gets the field object at the specified field index in the table.
int	get_FieldIndexByName (string Fieldname)
	Seeks field with specified name. Comparison is case insensitive.
object	get_MaxValue (int FieldIndex)
	Returns the maximum value for the specified field of the table.
double	get_MeanValue (int FieldIndex)
	Calculates the mean value for the specified field of the table.
object	get_MinValue (int FieldIndex)
	Returns the minimum value for the specified field.
double	get_StandardDeviation (int FieldIndex)
	Calculates the standard deviation for the set of values in specified field.
bool	Open (string dbfFilename, ICallback cBack)
	Opens a .dbf table from file.
bool	ParseExpression (string Expression, ref string ErrorString)
	Checks if the expression is a valid one.
bool	Query (string Expression, ref object Result, ref string ErrorString)
	Selects the rows in the table which agree with the specified expression.
bool	Save (ICallback cBack)
	Saves in-memory version of the table to the source file.
bool	SaveAs (string dbfFilename, ICallback cBack)
	Saves the table using the specified filename.
bool	StartEditingTable (ICallback cBack)
	Sets the table to allow table editing.
bool	StopEditingTable (bool ApplyChanges, ICallback cBack)
	Sets the table to prevent editing.
bool	TestExpression (string Expression, tkValueType ReturnType, ref string ErrorString)
	Tests the validity of expression and determines its return type.
Properties
string	CdlgFilter [get]
	Returns the common dialog filter containing all supported file extensions in string format.
bool	EditingTable [get]
	Gets whether or not the table is in editing mode.
ICallback	GlobalCallback [get, set]
	The global callback is the interface used by MapWinGIS to pass progress and error events to interested applications.
string	Key [get, set]
	The key may be used by the programmer to store any string data associated with the object.
int	LastErrorCode [get]
	Retrieves the last error generated in the object.
int	NumFields [get]
	Gets the number of fields in the table.
int	NumRows [get]
	Gets the number of rows in the table.

---

Detailed Description

The table object is used to store information from the dbf file associated with a shapefile.

Graph description

The following code will add the field in the table:

 Shapefile sf = some_shapefile;
 if (sf.EditingTable)
 {
     // string field
     Field fld = new Field();
     fld.Name = "New field";
     fld.Type = FieldType.STRING_FIELD;
     fld.Width = 15;      // 15 characters

     // let's insert it
     int fieldIndex = sf.NumFields;      // it will be inserted as the last one
     sf.EditInsertField(fld, ref fieldIndex, null);
 }

To find the index of field with the given name in the table:

 Shapefile sf = some_shapefile;
    
 // fast call
 int fieldIndex = sf.Table.get_FieldIndexByName("New field");

 // to do the same "manually"
 fieldIndex = -1;
 for (int i = 0; i < sf.NumFields; i++)
 {
     if (sf.get_Field(i).Name == "New field") {
         fieldIndex = i;
         break;
     }
 }

 Debug.Print("Field index: " + fieldIndex.ToString());

---

Member Function Documentation

bool Table.Calculate	(	string	Expression,
		int	RowIndex,
		out object	Result,
		out string	ErrorString
	)

Calculates the the expression taking the values from the specified row of the atrribute table.

Parameters:

Expression	The expression to analyze.
RowIndex	The index of the row.
Result	The result of calculation as variant data type, either boolean, double or string.
ErrorString	An output string with the description of error in case method failed.

Returns:

True on successful calculation and false otherwise.

New API 4.8:

Added in version 4.8

bool Table.Close

(

)

Closes the attribute table.

Returns:

The value can be ignored.

bool Table.CreateNew

(

string

dbfFilename

)

Creates a new attribute table.

A new table is automatically in editing mode after it is created.

Parameters:

dbfFilename

The filename for the new table.

Returns:

A boolean value representing the success or failure of creating the new table.

int Table.EditAddField	(	string	Name,
		FieldType	Type,
		int	Precision,
		int	Width
	)

Adds a field to the table. The table must be in editing mode.

Parameters:

Name	The name of field.
Type	The type of field.
Precision	The precision of field.
Width	The width of field.

Returns:

The index of the new field or -1 on failure.

bool Table.EditCellValue	(	int	FieldIndex,
		int	RowIndex,
		object	newVal
	)

Sets the value of the cell.

The table must be set to allow editing before a cell's value may be edited.

Parameters:

FieldIndex	The field index of the cell to be edited.
RowIndex	The row index of the cell to be edited.
newVal	The new value to be used to set the specified cell's value.

Returns:

A boolean value representing the success or failure of setting the value of the specified cell in the table.

bool Table.EditClear

(

)

Deletes all rows and fields from the table. Note: The table must be set to allow editing before the rows and fields can be deleted from the table.

Returns:

A boolean value representing the success or failure of deleting all rows and fields from the table.

bool Table.EditDeleteField	(	int	FieldIndex,
		ICallback	cBack
	)

Deletes a field from the table.

The table must be set to allow editing before a field can be deleted from the table.

Parameters:

FieldIndex	The index of the field to be deleted from the table.
cBack	The ICallback object which will receive progress and error messages while the field is being deleted from the table.

Returns:

bool Table.EditDeleteRow

(

int

RowIndex

)

Deletes a row from the table.

The table must be set to allow editing before a row can be deleted from the table.

Parameters:

RowIndex

The index of the row to be deleted from the table.

Returns:

A boolean value representing the success or failure of deleting the specified row from the table.

bool Table.EditInsertField	(	Field	Field,
		ref int	FieldIndex,
		ICallback	cBack
	)

Inserts a new field into the table.

The table must be set to allow editing before a field can be inserted into the table.

Parameters:

Field	The new field to be inserted into the table.
FieldIndex	The desired index to be used for the new field being inserted into the table. If the desired index is invalid or unavailable, the actual index used for the new field will be returned.
cBack	The ICallback object which will receive progress and error messages while the new field is being inserted into the table.

Returns:

A boolean value representing the success or failure of inserting the new field into the table.

bool Table.EditInsertRow

(

ref int

RowIndex

)

Inserts a new row into the table.

The table must be set to allow editing before a row can be inserted into the table.

Parameters:

RowIndex

The desired index to use when inserting the new row into the table. If the desired index is invalid or unavailable, the actual index used to insert the new row will be returned.

Returns:

A boolean value representing the success or failure of inserting the new row into the table.

bool Table.EditReplaceField	(	int	FieldIndex,
		Field	NewField,
		ICallback	cBack
	)

Replaces the specified field in the table with the new field.

The table must be set to allow editing before a field can be replaced in the table.

Parameters:

FieldIndex	The index of the field to be replaced.
NewField	The field to be used to replace the specified field in the table.
cBack	The ICallback object which will receive progress and error messages while the specified field is being replced by the new field.

Returns:

A boolean value representing the success or failure of replacing the specified field.

object Table.get_CellValue	(	int	FieldIndex,
		int	RowIndex
	)

Gets the value of the specified cell in the table.

Parameters:

FieldIndex	The field index of the cell for which the value is required.
RowIndex	The row index of the cell for which the value is required.

Returns:

The value of the specified cell in the table.

Examples:

PointIcons.cs, and ZoomToValues.cs.

string Table.get_ErrorMsg

(

int

ErrorCode

)

Retrieves the error message associated with the specified error code.

Parameters:

ErrorCode

The error code for which the error message is required.

Returns:

The error message description for the specified error code.

Examples:

EditAttributes.cs, SelectBox.cs, and ToolTip.cs.

Field Table.get_Field

(

int

FieldIndex

)

Gets the field object at the specified field index in the table.

Parameters:

FieldIndex

The index of the field in the table to be returned.

Returns:

The field object specified by the field index.

Examples:

ShowAttributes.cs.

int Table.get_FieldIndexByName

(

string

Fieldname

)

Seeks field with specified name. Comparison is case insensitive.

Parameters:

Fieldname

The name of field to search.

Returns:

The index of field if it exists and -1 otherwise.

Examples:

AddCategoryRange.cs, CalculateArea.cs, EditAttributes.cs, PointIcons.cs, SplitByAttribute.cs, and ZoomToValues.cs.

object Table.get_MaxValue

(

int

FieldIndex

)

Returns the maximum value for the specified field of the table.

NULL will be returned in case of invalid index.

Parameters:

FieldIndex

The index of the field.

Returns:

The maximum value, either integer, double or string data type.

New API 4.8:

Added in version 4.8

Examples:

AddCategoryRange.cs.

double Table.get_MeanValue

(

int

FieldIndex

)

Calculates the mean value for the specified field of the table.

NULL will be returned in case of invalid index.

Parameters:

FieldIndex

The index of the field.

Returns:

The mean value, either integer, double or string data type.

New API 4.8:

Added in version 4.8

Examples:

AddCategoryRange.cs.

object Table.get_MinValue

(

int

FieldIndex

)

Returns the minimum value for the specified field.

NULL will be returned in case of invalid index.

Parameters:

FieldIndex

The index of the field.

Returns:

The minimum value, either integer, double or string data type.

New API 4.8:

Added in version 4.8

Examples:

AddCategoryRange.cs.

double Table.get_StandardDeviation

(

int

FieldIndex

)

Calculates the standard deviation for the set of values in specified field.

NULL will be returned in case of invalid index.

Parameters:

FieldIndex

The index of the field.

Returns:

The minimum value, either integer, double or string data type.

New API 4.8:

Added in version 4.8

Examples:

AddCategoryRange.cs.

bool Table.Open	(	string	dbfFilename,
		ICallback	cBack
	)

Opens a .dbf table from file.

Parameters:

dbfFilename	The filename of the table to be opened.
cBack	The ICallback object which will receive progress and error messages while the table is being opened.

Returns:

The boolean value representing success or failure of the opening table.

bool Table.ParseExpression	(	string	Expression,
		ref string	ErrorString
	)

Checks if the expression is a valid one.

Parameters:

Expression	The expression to analyze.
ErrorString	An output string with the description of error in case expression is not valid.

Returns:

True if expression is valid and false otherwise.

New API 4.8:

Added in version 4.8

bool Table.Query	(	string	Expression,
		ref object	Result,
		ref string	ErrorString
	)

Selects the rows in the table which agree with the specified expression.

Parameters:

Expression	The query expression.
Result	An array of integer type with the indices of rows which were selected.
ErrorString	An output string with the description of error on failure.

Returns:

True in case at least one row was selected and false otherwise.

New API 4.8:

Added in version 4.8

Examples:

SelectByQuery.cs.

bool Table.Save

(

ICallback

cBack

)

Saves in-memory version of the table to the source file.

This method should be called while the table is in editing mode. The editing mode will not be closed.

Parameters:

cBack

A callback object to report information about progress and errors.

Returns:

True on success and false otherwise.

New API 4.8:

Added in version 4.8

bool Table.SaveAs	(	string	dbfFilename,
		ICallback	cBack
	)

Saves the table using the specified filename.

Parameters:

dbfFilename	The filename to be used to save the table.
cBack	The ICallback object which will receive progress and error messages while the table is being saved.

Returns:

A boolean value representing the success or failure of saving the table.

bool Table.StartEditingTable

(

ICallback

cBack

)

Sets the table to allow table editing.

Parameters:

cBack

Optional. The ICallback object which will receive progress and error events while the table is being set to allow editing.

Returns:

A boolean value representing the success or failure of setting the table to allow editing.

Examples:

EditAttributes.cs.

bool Table.StopEditingTable	(	bool	ApplyChanges,
		ICallback	cBack
	)

Sets the table to prevent editing.

Parameters:

ApplyChanges	Optional. A boolean value representing whether or not to save changes to the table. The default is True, to save the changes.
cBack	Optional. The ICallback object which will receive progress and error messages while the table is being set to prevent editing.

Returns:

A boolean value representing the success or failure of setting the table to prevent editing.

bool Table.TestExpression	(	string	Expression,
		tkValueType	ReturnType,
		ref string	ErrorString
	)

Tests the validity of expression and determines its return type.

Parameters:

Expression	The expression to test.
ReturnType	An output value with the return type, either double, string or boolean.
ErrorString	An output string with the description of error.

Returns:

True if the expression is valid and false otherwise.

New API 4.8:

Added in version 4.8

---

Property Documentation

string Table.CdlgFilter [get]

Returns the common dialog filter containing all supported file extensions in string format.

bool Table.EditingTable [get]

Gets whether or not the table is in editing mode.

ICallback Table.GlobalCallback [get, set]

The global callback is the interface used by MapWinGIS to pass progress and error events to interested applications.

string Table.Key [get, set]

The key may be used by the programmer to store any string data associated with the object.

int Table.LastErrorCode [get]

Retrieves the last error generated in the object.

int Table.NumFields [get]

Gets the number of fields in the table.

int Table.NumRows [get]

Gets the number of rows in the table.

Examples:

PointIcons.cs.