events - DatagridViewComboboxCell value changed in C# -

i have datagridviewcombobox column , creating datagridviewcombobox cells on each row , adding items it. when change value of (combobox) cell, throws exception saying datagridviewcombobox cell value not valid. , cell value becomes '1'.

i working on datagridview_currentcelldirtystatechange event, haven't been able make work.

the code below creating rows , filling combobox cells sequence numbers.

    int _rowlimit =1;      (int = _rowlimit - 1; < _rowlimit; i++)     {                    datagridview.rows.add();          item = + 1;          datagridview[mycolumn, i].value = _rowlimit;                              datagridviewcomboboxcell ocell = datagridview.currentrow.cells[mycolumn] datagridviewcomboboxcell;          ocell.items.add(item);           ((datagridviewcomboboxcolumn)datagridview.columns[mycolumn]).items.indexof(_rowlimit);          ((datagridviewcomboboxcolumn)datagridview.columns[mycolumn]).items.insert(index, item);     } 

and below doing in datagridview_currentcelldirtystatechange event:

for (int innerindex = 0; innerindex < datagridview.rows.count; innerindex++)     {       long sequence = 3;       long oldsequence = 2;       long tempvalue= convert.toint64(datagridview.rows[innerindex].cells[mycolumn].value);       if (tempvalue <= sequence && tempvalue> oldsequence)       {                                datagridview.rows[innerindex].cells[mycolumn].value = tempvalue+ 1; // increment   sequence  // value here getting correct , doesn't show in datagridviewcombobox cell gets changed of gridview , mentioned exception thrown.        } 

any appreciated. thanks.

the error on selectedindexchange value of combobox cells , exception of datagridviewcomboboxcell value not valid .. automatically did change selected vlue '1'.. fixed issue adding datagridviewcomboboxcolumn property in designer file.

this.columnname.valuetype = typeof(long);  

typeof(long) // what wanted show value in datagridviewcombobox column.

issue has resolved. thanks.