向下模拟CTRL直到我想要使用C＃？

Question

I'm trying to simulate a user pressing ctrl down, the main goal would be in a datagridview when I select something programarly (initially) I dont want the user to then change that selection if not just add on to it or subtract, just as if you were to hold ctrl + left mouse click. I have no idea where to even begin. I tried to create a selection change event conbined with logicals but that will cause an infinite loop since we would be selecting one by a user then the code change other and other etc infinitely triggering that event. Please help, I'm sort of new to coding. I also don't know how to determine whether a ctrl key has been pressed, is pressed and being held.

        private void selecttionh(object sender, EventArgs e)
    {

        if (stage == "4A" || stage == "3B" && ModifierKeys.HasFlag(Keys.Control))
        {
            int nothing = 0;
            btnclickercl bt = new btnclickercl();
            bt.dataGridView1_SelectionChanged(sender, e, dataGridViewReslist, dataGridViewnewres, nothing);
        }
        if (stage == "4A" || stage == "3B" && (ModifierKeys & Keys.Control) != Keys.Control)
        {
            MessageBox.Show("Please Press and hold " + "'ctrl'" + " to continue");
            dataGridViewReslist.ClearSelection();
            for (int i = 0; i < ResRoomSelections.Count; i++)
            {
                dataGridViewReslist.Rows[ResRoomSelections[i][0]].Cells[ResRoomSelections[i][1]].Selected = true;
                dataGridViewReslist.Rows[ResRoomSelections[i][0]].Cells[(ResRoomSelections[i][1]) + 1].Selected = true;
            }
        }
        else
        {
                dataGridViewReslist.ClearSelection();
                for (int i = 0; i < ResRoomSelections.Count; i++)
                {
                    dataGridViewReslist.Rows[ResRoomSelections[i][0]].Cells[ResRoomSelections[i][1]].Selected = true;
                    dataGridViewReslist.Rows[ResRoomSelections[i][0]].Cells[(ResRoomSelections[i][1]) + 1].Selected = true;
                }
        }  

    }

Answer 1

The way to make this happen is to store the selection state separately, update it when the user clicks a cell, then re-apply it. This prevents the selection from being lost every time they click. If you hook the proper event handlers (mouseup, not click) you can do this without the screen flickering and otherwise being a mess to look at.

Everything you need is in this class, including an extension method SetupToggledSelectionMode() , which is your entry point.

static public class Example
{
    static private bool[][] GetSelectionState(DataGridView input)
    {
        int rowCount = input.Rows.Count;
        int columnCount = input.Columns.Count;
        var result = new bool[rowCount][];
        for (var r = 0; r < rowCount; r++)
        {
            result[r] = new bool[columnCount];
            for (var c = 0; c < columnCount; c++)
            {
                var cell = input.Rows[r].Cells[c];
                result[r][c] = cell.Selected;
            }
        }
        return result;
    }

    static private void SetSelectionState(DataGridView input, bool[][] selectionState)
    {
        for (int r = 0; r <= selectionState.GetUpperBound(0); r++)
        {
            for (int c = 0; c <= selectionState[r].GetUpperBound(0); c++)
            {
                input.Rows[r].Cells[c].Selected = selectionState[r][c];
            }
        }
    }


    static public void SetupToggledSelectionMode(this DataGridView input)
    {
        bool[][] selectionState = GetSelectionState(input);  //This will be stored in a closure due to the lambda expressions below

        input.CellMouseUp += (object sender, DataGridViewCellMouseEventArgs e) =>
        {
            selectionState[e.RowIndex][e.ColumnIndex] = !selectionState[e.RowIndex][e.ColumnIndex];
            SetSelectionState(input, selectionState);
        };

        input.SelectionChanged += (object sender, EventArgs e) =>
        {
            if (selectionState != null)
            {
                SetSelectionState(input, selectionState);
            }
        };
    }
}

To use, populate your gridview, set up the initial selection programmatically, and call it like this:

myDataGrid.DataSource = myData;
myDataGrid.Refresh();
myDataGrid.SelectAll();
myDataGrid.SetupToggledSelectionMode();

The SetupToggledSelectionMode() method will register the necessary event handlers and store the selection state of the grid in a closed variable accessible to both handlers. So you won't have to declare anything additional; just call the method.

Answer 2

Thank you for this, this really helped me. all I did was to make it more efficient.Since it would call the Selection change every step of the way, so I got rid of that event completely and only kept the CellMouseup Event.

static private bool[][] GetSelectionState(DataGridView input)
{
    int rowCount = input.Rows.Count;
    int columnCount = input.Columns.Count;
    var result = new List<int[]>();
    for (var r = 0; r < rowCount; r++)
    {
        for (var c = 0; c < columnCount; c++)
        {
            if(input.Rows[r].Cells[c].Selected==true)
           {
            result.add(new int[]{r,c});//will keep only the integer of selected items
           }
        }
    }
    return result;//this for me was a recycled variable it can be used or recycled from somewhere else
}

private void SetSelectionState(DataGridView input,result)
    {
        for (int i=0;i<result.Count;i++)
        {
            input.Rows[result[i][0]].Cells[result[i][1]].Selected = true;

        }
    }
public void SetupToggledSelectionMode(DataGridView input,result)
    {
     for (int i=0;i<result.Count;i++)
            {
                if(result[i].SequenceEqual(new int[] { e.RowIndex, e.ColumnIndex }))
                {
                    result.RemoveAt(i);
                    continueer = 1;
                    break;
                }
            }
            if (continueer == 0)
            {
                ResRoomSelections.Add(new int[] { e.RowIndex, e.ColumnIndex });
            }
        SetSelectionState(input);
         //whatever else you need to do 
 }

I know there is still a better way to search List but I could not get a lamda search to work so I just used brute force

-Thank you John Wu for all