Winforms datagridview:拖放导致错误
Winforms datagridview : drag and drop causes an error
System.Windows.Forms.dll 中发生类型 'System.InvalidOperationException' 的异常,但未在用户代码中处理
附加信息:无法以编程方式删除行,除非 DataGridView 数据绑定到支持更改通知并允许删除
的 IBindingList
这就是我将数据绑定到 datagridview 的方式:
IEnumerable<myTable> query = from p in db.myTables select p;
testList = query.ToList();
dataGridView1.DataSource = testList;
这就是我用来拖放行的方法:
private void dataGridView1_MouseClick(object sender, MouseEventArgs e)
{
if (dataGridView1.SelectedRows.Count == 1)
{
if (e.Button == MouseButtons.Left)
{
rw = dataGridView1.SelectedRows[0];
rowIndexFromMouseDown = dataGridView1.SelectedRows[0].Index;
dataGridView1.DoDragDrop(rw, DragDropEffects.Move);
}
}
}
private void dataGridView1_DragEnter(object sender, DragEventArgs e)
{
if (dataGridView1.SelectedRows.Count > 0)
{
e.Effect = DragDropEffects.Move;
}
}
private void dataGridView1_DragDrop(object sender, DragEventArgs e)
{
int rowIndexOfItemUnderMouseToDrop;
Point clientPoint = dataGridView1.PointToClient(new Point(e.X, e.Y));
rowIndexOfItemUnderMouseToDrop = dataGridView1.HitTest(clientPoint.X, clientPoint.Y).RowIndex;
if (e.Effect == DragDropEffects.Move)
{
dataGridView1.Rows.RemoveAt(rowIndexFromMouseDown);
dataGridView1.Rows.Insert(rowIndexOfItemUnderMouseToDrop, rw);
}
}
每当我尝试拖放时,拖放是可以的,但拖放会导致我上面提到的错误,如果可能的话,我不想使用绑定列表,因为如果我使用它,我将不得不进行很多更改。
如果您能提供帮助,我将不胜感激。
我解决了这个问题。我对鼠标事件进行了更改
private void dataGridView1_MouseMove(object sender, MouseEventArgs e)
{
if ((e.Button & MouseButtons.Left) == MouseButtons.Left)
{
if (dragBoxFromMouseDown != Rectangle.Empty && !dragBoxFromMouseDown.Contains(e.X, e.Y))
{
DragDropEffects dropEffect = dataGridView1.DoDragDrop(dataGridView1.Rows[rowIndexFromMouseDown], DragDropEffects.Copy);
}
}
}
private void dataGridView1_MouseDown(object sender, MouseEventArgs e)
{
// Get the index of the item the mouse is below.
rowIndexFromMouseDown = dataGridView1.HitTest(e.X, e.Y).RowIndex;
if (rowIndexFromMouseDown != -1)
{
Size dragSize = SystemInformation.DragSize;
dragBoxFromMouseDown = new Rectangle(new Point(e.X - (dragSize.Width / 2), e.Y - (dragSize.Height / 2)), dragSize);
}
else
dragBoxFromMouseDown = Rectangle.Empty;
}
private void dataGridView1_DragOver(object sender, DragEventArgs e)
{
e.Effect = DragDropEffects.Copy;
}
private void dataGridView1_DragDrop(object sender, DragEventArgs e)
{
try
{
if (e.Data.GetDataPresent(typeof(DataGridViewRow)))
{
Point clientPoint = dataGridView1.PointToClient(new Point(e.X, e.Y));
if (e.Effect == DragDropEffects.Copy)
{
DataGridViewRow Row = (DataGridViewRow)e.Data.GetData(typeof(DataGridViewRow));
dataGridView1.Rows.Add(Row.Cells[0].Value, Row.Cells[1].Value, Row.Cells[2].Value);
}
}
else
{
//Reflect the exception to screen
MessageBox.Show("Geen data! #01", "Error");
}
}
catch (Exception msg)
{
MessageBox.Show(msg.Message, "Error");
}
}
System.Windows.Forms.dll 中发生类型 'System.InvalidOperationException' 的异常,但未在用户代码中处理 附加信息:无法以编程方式删除行,除非 DataGridView 数据绑定到支持更改通知并允许删除
的 IBindingList这就是我将数据绑定到 datagridview 的方式:
IEnumerable<myTable> query = from p in db.myTables select p;
testList = query.ToList();
dataGridView1.DataSource = testList;
这就是我用来拖放行的方法:
private void dataGridView1_MouseClick(object sender, MouseEventArgs e)
{
if (dataGridView1.SelectedRows.Count == 1)
{
if (e.Button == MouseButtons.Left)
{
rw = dataGridView1.SelectedRows[0];
rowIndexFromMouseDown = dataGridView1.SelectedRows[0].Index;
dataGridView1.DoDragDrop(rw, DragDropEffects.Move);
}
}
}
private void dataGridView1_DragEnter(object sender, DragEventArgs e)
{
if (dataGridView1.SelectedRows.Count > 0)
{
e.Effect = DragDropEffects.Move;
}
}
private void dataGridView1_DragDrop(object sender, DragEventArgs e)
{
int rowIndexOfItemUnderMouseToDrop;
Point clientPoint = dataGridView1.PointToClient(new Point(e.X, e.Y));
rowIndexOfItemUnderMouseToDrop = dataGridView1.HitTest(clientPoint.X, clientPoint.Y).RowIndex;
if (e.Effect == DragDropEffects.Move)
{
dataGridView1.Rows.RemoveAt(rowIndexFromMouseDown);
dataGridView1.Rows.Insert(rowIndexOfItemUnderMouseToDrop, rw);
}
}
每当我尝试拖放时,拖放是可以的,但拖放会导致我上面提到的错误,如果可能的话,我不想使用绑定列表,因为如果我使用它,我将不得不进行很多更改。 如果您能提供帮助,我将不胜感激。
我解决了这个问题。我对鼠标事件进行了更改
private void dataGridView1_MouseMove(object sender, MouseEventArgs e)
{
if ((e.Button & MouseButtons.Left) == MouseButtons.Left)
{
if (dragBoxFromMouseDown != Rectangle.Empty && !dragBoxFromMouseDown.Contains(e.X, e.Y))
{
DragDropEffects dropEffect = dataGridView1.DoDragDrop(dataGridView1.Rows[rowIndexFromMouseDown], DragDropEffects.Copy);
}
}
}
private void dataGridView1_MouseDown(object sender, MouseEventArgs e)
{
// Get the index of the item the mouse is below.
rowIndexFromMouseDown = dataGridView1.HitTest(e.X, e.Y).RowIndex;
if (rowIndexFromMouseDown != -1)
{
Size dragSize = SystemInformation.DragSize;
dragBoxFromMouseDown = new Rectangle(new Point(e.X - (dragSize.Width / 2), e.Y - (dragSize.Height / 2)), dragSize);
}
else
dragBoxFromMouseDown = Rectangle.Empty;
}
private void dataGridView1_DragOver(object sender, DragEventArgs e)
{
e.Effect = DragDropEffects.Copy;
}
private void dataGridView1_DragDrop(object sender, DragEventArgs e)
{
try
{
if (e.Data.GetDataPresent(typeof(DataGridViewRow)))
{
Point clientPoint = dataGridView1.PointToClient(new Point(e.X, e.Y));
if (e.Effect == DragDropEffects.Copy)
{
DataGridViewRow Row = (DataGridViewRow)e.Data.GetData(typeof(DataGridViewRow));
dataGridView1.Rows.Add(Row.Cells[0].Value, Row.Cells[1].Value, Row.Cells[2].Value);
}
}
else
{
//Reflect the exception to screen
MessageBox.Show("Geen data! #01", "Error");
}
}
catch (Exception msg)
{
MessageBox.Show(msg.Message, "Error");
}
}