//=====================================================================
/// <summary>
/// Constructor
/// </summary>
/// <remarks>By default, the combo box will display all columns in its data source without row or column
/// headers, all columns will be auto-sized to the longest item within each column, and auto-completion
/// is enabled.</remarks>
public MultiColumnComboBox()
{
this.MouseTracking = true;
ddsDropDownFormat = new DropDownTableStyle();
ddsDropDownFormat.GridColumnStyles.CollectionChanged += GridColumnStyles_CollectionChanged;
}
//=====================================================================
/// <summary>
/// Constructor
/// </summary>
/// <remarks>By default, the combo box will display all columns in its data source without row or column
/// headers, all columns will be auto-sized to the longest item within each column, and auto-completion
/// is enabled.</remarks>
public MultiColumnComboBox()
{
this.MouseTracking = true;
ddsDropDownFormat = new DropDownTableStyle();
ddsDropDownFormat.GridColumnStyles.CollectionChanged += GridColumnStyles_CollectionChanged;
}
/// <summary>
/// This is used to initialize the drop-down styles and data source
/// </summary>
private void InitDropDown()
{
DropDownTableStyle ddts = owner.DropDownFormat;
int rowCount, rowHeight, headerHeight = 0, idx = 0, totalSize = 0, rowHeaderWidth = ddts.RowHeaderWidth;
// Must check this before we set the data source otherwise, columns are added by default
bool autoSize = (ddts.GridColumnStyles.Count == 0);
dgDropDown.Font = owner.DropDownFont;
dgDropDown.RightToLeft = owner.RightToLeft;
this.BackColor = dgDropDown.BackgroundColor = owner.DropDownBackColor;
this.Cursor = owner.Cursor;
// Set the data source and apply style settings. If there is a data source, use it.
ddts.MappingName = owner.MappingName;
dgDropDown.DataMember = owner.BindingPath;
if (owner.DataSource != null)
{
// If bound to a relationship, use the object collection
if (ddts.MappingName == dgDropDown.DataMember && ddts.MappingName.IndexOf('.') != -1)
{
ddts.MappingName = "ObjectCollection";
dgDropDown.TableStyles.Add(ddts);
dgDropDown.DataSource = owner.Items;
}
else
{
dgDropDown.TableStyles.Add(ddts);
dgDropDown.DataSource = owner.DataSource;
}
}
else
if (ddts.MappingName == "ValueType" || ddts.MappingName == "String")
{
// Value and string types require a wrapper or they don't show up correctly
ValueItem[] viArray = new ValueItem[owner.Items.Count];
for (int collIdx = 0; collIdx < owner.Items.Count; collIdx++)
{
viArray[collIdx] = new ValueItem(owner.Items[collIdx]);
}
ddts.MappingName = "ValueItem[]";
dgDropDown.TableStyles.Add(ddts);
dgDropDown.DataSource = viArray;
}
else // It must be an object collection
{
dgDropDown.DataSource = owner.Items;
}
// Filter the columns if necessary and clear the headers if auto-sizing and they aren't visible.
// Clearing the header text is necessary so that we get an accurate size.
StringCollection filter = owner.ColumnFilter;
if (filter.Count != 0 || (autoSize && !ddts.ColumnHeadersVisible))
{
for (idx = 0; idx < ddts.GridColumnStyles.Count; idx++)
{
if (filter.Count != 0 && !filter.Contains(ddts.GridColumnStyles[idx].MappingName))
{
ddts.GridColumnStyles.RemoveAt(idx);
idx--;
}
else
if (autoSize && !ddts.ColumnHeadersVisible)
{
ddts.GridColumnStyles[idx].HeaderText = String.Empty;
}
}
}
// Row Header Width and Column Headers Visible seem to get overridden so restore them
ddts.RowHeaderWidth = rowHeaderWidth;
dgDropDown.ColumnHeadersVisible = ddts.ColumnHeadersVisible;
// Only auto-size if the user didn't specify any columns
if (autoSize)
{
DataGridHelper.AutoSizeColumns(dgDropDown);
}
// Sum the width of the columns and take the opportunity to auto-size columns with a width of zero.
// This only happens if the user specified column definitions.
idx = 0;
foreach (DataGridColumnStyle col in ddts.GridColumnStyles)
{
// Replace default null text where needed
if (col.NullText == "(null)")
{
col.NullText = ddts.DefaultNullText;
}
if (col.Width == 0)
{
DataGridHelper.AutoSizeColumn(dgDropDown, idx);
}
totalSize += col.Width;
idx++;
}
// Use the specified width or figure out the initial width
if (owner.DropDownWidth != 0)
{
totalSize = owner.DropDownWidth;
}
else
{
if (ddts.RowHeadersVisible)
{
totalSize += rowHeaderWidth;
}
if (idx != 0 && totalSize < owner.Width - 2)
{
// Stretch the last column to fit the width
ddts.GridColumnStyles[idx - 1].Width += owner.Width - totalSize - 2;
totalSize = owner.Width;
}
else
if (idx == 0)
{
totalSize = owner.Width;
}
else
{
totalSize += 2;
}
}
// Enforce a minimum width
if (totalSize < 30)
{
totalSize = 30;
}
this.Width = totalSize;
// Set default height
rowCount = DataGridHelper.RowCount(dgDropDown);
if (rowCount != 0 && ddts.GridColumnStyles.Count > 0)
{
rowHeight = dgDropDown.GetCellBounds(0, 0).Height + 1;
}
else
{
rowHeight = dgDropDown.PreferredRowHeight;
}
// Figure out column header height if visible. This is a little ugly but it works.
if (ddts.ColumnHeadersVisible)
{
while (dgDropDown.HitTest(rowHeaderWidth + 2, headerHeight).Type == DataGrid.HitTestType.ColumnHeader)
{
headerHeight++;
}
}
if (rowCount > owner.MaxDropDownItems)
{
rowHeight = (rowHeight * owner.MaxDropDownItems) + headerHeight;
// Adjust width to account for the scrollbar
this.Width += MultiColumnComboBox.DropDownButtonWidth;
}
else
{
rowHeight = (rowHeight * rowCount) + headerHeight;
}
this.Height = rowHeight + this.Height - dgDropDown.Height;
hasInitialized = true;
}