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Hi all,
I would like to display nothing when the user chooses the first option of the combobox.
In Visual Basic 6.0 I would use something like that :
DataGridViewComboBoxColumn.SelectedIndex = -1
I use the newest VS 2005 (no beta).
Thanks !
Best regards,
Joao Araujo | | Joccar Wednesday, November 30, 2005 5:14 PM | I got it ! I inserted a new row into the DataTable object. Then the user can select an empty option that saves the NULL value into the database column. Yeahh! Best regards, Joao Araujo | |
// create a new combobox column.
DataGridViewComboBoxColumn dgvc = new DataGridViewComboBoxColumn();
// set the column width
dgvc.Width = Width; // set the database column which it is bound
dgvc.DataPropertyName = FieldName; // set the column name
dgvc.Name = FieldName; // set the header text
dgvc.HeaderText = HeaderText; DataTable MyTable = CreateDataTable(sql, TableName, false);
AddNullValueForDataTable(MyTable, DisplayMember, ValueMember);
dgvc.DataSource = MyTable;
dgvc.DisplayMember = DisplayMember;
dgvc.ValueMember = ValueMember; // add the column into the grid
dgrView.Columns.Add(dgvc);
/// <summary>
/// Adds null values into the DataTable. The value member is empty and
/// the display member contains DBNull.Value.
/// </summary>
/// <param name="datatable">The source DataTable used to fill the combobox.</param>
/// <param name="DisplayMember">String that specifies the property of the data source whose contents you want to display.</param>
/// <param name="ValueMember">String that specifies the property of the data source from which to draw the value.</param>
/// <returns>The adcional string to add to the select statement.</returns>
public static void AddNullValueForDataTable(DataTable datatable
, string DisplayMember
, string ValueMember)
{
try
{
// allows NULL values
datatable.Columns[ValueMember].AllowDBNull = true;
// create a new row
DataRow row = datatable.NewRow();
// set the values
row[DisplayMember] = " ";
row[ValueMember] = DBNull.Value;
// add to the DataTable
datatable.Rows.InsertAt(row, 0);
}
catch (Exception e)
{
Sky4Main.MessageError(e);
}
}
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| | Joccar Wednesday, November 30, 2005 6:52 PM | One other way, the DataGridView supports the Ctrl+0 keystroke to enter a null value into a cell, so you can use that to clear out a combo box's value and set it back to null.
-mark
DataGridView Program Manager
Microsoft
This post is provided "as-is" | | Mark Rideout Wednesday, November 30, 2005 7:18 PM | I got it ! I inserted a new row into the DataTable object. Then the user can select an empty option that saves the NULL value into the database column. Yeahh! Best regards, Joao Araujo | |
// create a new combobox column.
DataGridViewComboBoxColumn dgvc = new DataGridViewComboBoxColumn();
// set the column width
dgvc.Width = Width; // set the database column which it is bound
dgvc.DataPropertyName = FieldName; // set the column name
dgvc.Name = FieldName; // set the header text
dgvc.HeaderText = HeaderText; DataTable MyTable = CreateDataTable(sql, TableName, false);
AddNullValueForDataTable(MyTable, DisplayMember, ValueMember);
dgvc.DataSource = MyTable;
dgvc.DisplayMember = DisplayMember;
dgvc.ValueMember = ValueMember; // add the column into the grid
dgrView.Columns.Add(dgvc);
/// <summary>
/// Adds null values into the DataTable. The value member is empty and
/// the display member contains DBNull.Value.
/// </summary>
/// <param name="datatable">The source DataTable used to fill the combobox.</param>
/// <param name="DisplayMember">String that specifies the property of the data source whose contents you want to display.</param>
/// <param name="ValueMember">String that specifies the property of the data source from which to draw the value.</param>
/// <returns>The adcional string to add to the select statement.</returns>
public static void AddNullValueForDataTable(DataTable datatable
, string DisplayMember
, string ValueMember)
{
try
{
// allows NULL values
datatable.Columns[ValueMember].AllowDBNull = true;
// create a new row
DataRow row = datatable.NewRow();
// set the values
row[DisplayMember] = " ";
row[ValueMember] = DBNull.Value;
// add to the DataTable
datatable.Rows.InsertAt(row, 0);
}
catch (Exception e)
{
Sky4Main.MessageError(e);
}
}
|
| | Joccar Wednesday, November 30, 2005 6:52 PM | One other way, the DataGridView supports the Ctrl+0 keystroke to enter a null value into a cell, so you can use that to clear out a combo box's value and set it back to null.
-mark
DataGridView Program Manager
Microsoft
This post is provided "as-is" | | Mark Rideout Wednesday, November 30, 2005 7:18 PM | | Mark Rideout wrote: | | One other way, the DataGridView supports the Ctrl+0 keystroke to enter a null value into a cell, so you can use that to clear out a combo box's value and set it back to null.
-mark
DataGridView Program Manager
Microsoft
This post is provided "as-is" |
|
Thanks Mark ! It was very helpful for me, but for the 200 people that will use the program, I think this option is for them not so user friendly ! Kind Regards ! Joao Araujo | | Joccar Thursday, December 01, 2005 11:01 AM |
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