Working with the Count Property

Determine the number of objects in a collection using the collection's Count property:

· Visual Basic

' Set a variable equal to the number of Splits in C1TrueDBGrid1.

variable = Me.C1TrueDBGrid1.Splits.Count

· C#

// Set a variable equal to the number of Splits in C1TrueDBGrid1.

variable = this.C1TrueDBGrid1.Splits.Count;

· Delphi

// Set a variable equal to the number of Splits in C1TrueDBGrid1.

variable := Self.C1TrueDBGrid1.Splits.Count;

Iterate through all objects in a collection using the Count property as in the following example, which prints the Caption string of each C1DataColumn object in a grid:

· Visual Basic

For n = 0 To Me.C1TrueDBGrid1.Columns.Count - 1

Debug.WriteLine(Me.C1TrueDBGrid1.Columns(n).Caption)

Next n

· C#

for (n = 0; n < this.c1TrueDBGrid1.Columns.Count; n++)

{

Console.WriteLine(this.c1TrueDBGrid1.Columns[n].Caption);

}

· Delphi

for n := 0 to Self.C1TrueDBGrid1.Columns.Count – 1 do

Debug.WriteLine(Self.C1TrueDBGrid1.Columns[n].Caption);

The Count property is also useful for appending and removing columns:

· Visual Basic

' Determine how many columns there are.

Dim NumCols As Integer

NumCols = Me.C1TrueDBGrid1.Columns.Count

' Append a column to the end of the Columns collection.

Dim C As C1TrueDBGrid.C1DataColumn = New C1TrueDBGrid.C1DataColumn()

Me.TrueDBGrid1.Columns.Insert(NumCols, C)

' Make the new column visible, since columns created at run time are invisible by default.

Me.TrueDBGrid1.Splits(0).DisplayColumns(C).Visible = True

' The following loop removes all columns from the grid.

While Me.C1TrueDBGrid1.Columns.Count

Me.C1TrueDBGrid1.Columns.RemoveAt(0)

End While

· C#

// Determine how many columns there are.

int NumCols;

NumCols = this.C1TrueDBGrid1.Columns.Count;

// Append a column to the end of the Columns collection.

C1TrueDBGrid.C1DataColumn C = new C1TrueDBGrid.C1DataColumn();

this.TrueDBGrid1.Columns.Insert(NumCols, C);

// Make the new column visible, since columns created at run time are invisible by default.

this.TrueDBGrid1.Splits[0].DisplayColumns[C].Visible = true;

// The following loop removes all columns from the grid.

while ( this.C1TrueDBGrid1.Columns.Count > 0 )

{

this.C1TrueDBGrid1.Columns.RemoveAt(0);

}

· Delphi

var NumCols: Integer;

C: C1TrueDBGrid.C1DataColumn;

// Determine how many columns there are.

NumCols := Self.C1TrueDBGrid1.Columns.Count;

// Append a column to the end of the Columns collection.

Self.TrueDBGrid1.Columns.Insert(NumCols, C);

// Make the new column visible, since columns created at run time are invisible by default.

Self.TrueDBGrid1.Columns[NumCols].Visible := True;

// The following loop removes all columns from the grid.

while (Self.C1TrueDBGrid1.Columns.Count > 0) do

Self.C1TrueDBGrid1.Columns.RemoveAt(0);

An efficient For Each...Next statement that can be used iterate through the objects in a collection without using the Count property:

· Visual Basic

Dim C As C1TrueDBGrid.C1DataColumn

For Each C In Me.C1TrueDBGrid1.Columns

Debug.WriteLine(C.Caption)

· C#

C1TrueDBGrid.C1DataColumn c;

foreach (c In this.C1TrueDBGrid1.Columns)

{

Console.WriteLine(c);

}

· Delphi

var C: C1TrueDBGrid.C1DataColumn;

i: Integer;

for i := 0 to Self.C1TrueDBGrid1.Columns.Count-1 do

begin

C := Self.C1TrueDBGrid1.Columns[i];

Debug.WriteLine(C.Caption);

end;

In fact, using the For Each...Next statement is the easiest way to iterate through the objects in a collection.