c# - How to rebind datasource to a winform DataGridView Combobox column? -

i have datagridview in winform 2 combo box columns: 1) companies, 2) accounts. want update accounts combo box according selected company. have code:

void recipientsdatagrid_editingcontrolshowing(object sender, datagridvieweditingcontrolshowingeventargs e)     {         try         {             combobox cb = e.control combobox;             if (cb != null)             {                 cb.selectedvaluechanged -= new eventhandler(companycombobox_selectedvaluechanged);                 cb.selectedvaluechanged += new eventhandler(companycombobox_selectedvaluechanged);             }         }         catch (exception ex)         {          }     }      private void companycombobox_selectedvaluechanged(object sender, eventargs e)     {         try         {             var currentcell = recipientsdatagrid.currentcelladdress;             if (currentcell.x == 3)             {                 var sendingcb = sender datagridviewcomboboxeditingcontrol;                 int companyid = sendingcb.selectedvalue.toint();                 datatable dtaccounts = m_customersfunctions.getcompanyaccounts(companyid);                  datagridviewcomboboxcell cboaccounts = (datagridviewcomboboxcell)recipientsdatagrid.rows[currentcell.y].cells["account"];                 cboaccounts.valuemember = "account_id";                 cboaccounts.displaymember = "accountname";                 cboaccounts.datasource = dtaccounts;                  int defaultaccountid = (from row in dtaccounts.asenumerable()                                         row.field<string>("accountname").endswith("*")                                         select row.field<int>("account_id")).firstordefault();                 if (defaultaccountid > 0)                     cboaccounts.value = defaultaccountid;             }         }         catch (exception ex)         {             messagebox.show(ex.message);         }     } 

it works fine in first time select company, when change company , try update data source accounts combo box i'm getting error:

i tried add items manualy , not datasource, , got same error. how can fix ? please...

try clear value of accounts cell before rebind it, this:

private void companycombobox_selectedvaluechanged(object sender, eventargs e) {     try     {         var currentcell = recipientsdatagrid.currentcelladdress;         if (currentcell.x == 3)         {             var sendingcb = sender datagridviewcomboboxeditingcontrol;             int companyid = sendingcb.selectedvalue.toint();             datatable dtaccounts = m_customersfunctions.getcompanyaccounts(companyid);              datagridviewcomboboxcell cboaccounts = (datagridviewcomboboxcell)recipientsdatagrid.rows[currentcell.y].cells["account"];             cboaccounts.value = null; //add code             cboaccounts.valuemember = "account_id";             cboaccounts.displaymember = "accountname";             cboaccounts.datasource = dtaccounts;              int defaultaccountid = (from row in dtaccounts.asenumerable()                                     row.field<string>("accountname").endswith("*")                                     select row.field<int>("account_id")).firstordefault();             if (defaultaccountid > 0)                 cboaccounts.value = defaultaccountid;         }     }     catch (exception ex)     {         messagebox.show(ex.message);     } }