Job data buttons missing limits checks lead to crash

[MaWa53]

Here are the already modified event handlers, since I can't commit to SVN.

 public int GetGridRow(DataGridView grid) {
        if (grid.CurrentCell != null)
            return grid.CurrentCell.RowIndex;
        else
            return -1;
    }

    private void Up_button_Click(object sender, EventArgs e) {
        var row = GetGridRow(JobData_GridView);
        if (row <= 0) return;
        Global.MoveItem(Cad.JobData, row, -1);
        JobData_GridView.CurrentCell = JobData_GridView[0, row - 1];
    }

    private void Down_button_Click(object sender, EventArgs e) {
        var row = GetGridRow(JobData_GridView);
        if (row >= JobData_GridView.Rows.Count-1) return;
        if (row != -1)
        {
            Global.MoveItem(Cad.JobData, row, +1);
            JobData_GridView.CurrentCell = JobData_GridView[0, row + 1];
        }
    }

    private void DeleteComponentGroup_button_Click(object sender, EventArgs e) {
        if (JobData_GridView.Rows.Count > 0)
        {
            var row = GetGridRow(JobData_GridView);
            Cad.JobData.RemoveAt(row);
        }
    }

[thethereza]

tweaked and added

    public int GetGridRow(DataGridView grid) {
        return (grid.CurrentCell != null) ? grid.CurrentCell.RowIndex : -1;
    }

    private void Up_button_Click(object sender, EventArgs e) {
        var row = GetGridRow(JobData_GridView);
        if (row <= 0) return;
        Global.MoveItem(Cad.JobData, row, -1);
        JobData_GridView.CurrentCell = JobData_GridView[0, row - 1];
    }

    private void Down_button_Click(object sender, EventArgs e) {
        var row = GetGridRow(JobData_GridView);
        if (row >= JobData_GridView.Rows.Count - 1) return;
        if (row != -1) {
            Global.MoveItem(Cad.JobData, row, +1);
            JobData_GridView.CurrentCell = JobData_GridView[0, row + 1];
        }
    }

    private void DeleteComponentGroup_button_Click(object sender, EventArgs e) {
        if (JobData_GridView.Rows.Count > 0) {
            var row = GetGridRow(JobData_GridView);
            if (row != -1)  Cad.JobData.RemoveAt(row);
        }
    }