c# - Bind a DataGridViewComboBoxColumn to a DataGridView column -

i struggling few days problem , can not fix myself.

i have 3 datagridviews

• alphabet
• state
• transition

alphabet contains 1 column chars example 'a', 'b' , 'c'

state contains 3 columns: 'name'; 'is start state' , 'is end state'. first string column. other 2 checkbox columns.

transition contains 3 columns. (combobox), (combobox), symbol (combobox)

my goal use data user entered in state & alphabet tables comboboxes.

for example: user entered in alphabet folowing data: 'a' , 'b' user entered in state folowing data:

• lr_0; start state; no end state
• lr_1; no start state; no end state
• lr_2; no start state; end state

when user want fill transitions can choose column 'from' , 'to' de folowing options: lr_0; lr_1 or lr_2. symbol can use 'a' or 'b'.

now comes tricky part. when user rename lr_0 lr_3 comboboxes need update. , when user removes lr_0 row rows in transitions contains lr_0 needs remove.

i've used lot of posibilities none working 100% correct.

option 1 use intern list , bind bind comboboxes , everytime there row added add list. when there row removed remove list , remove every row in transitions contains value.

problems: unknown when there value changed , when value added. difficult change value in comboboxes

option 2 use ilist interface , make enumerator folowing datagridview information .rows.count = length , .rows[0].cells[0].value = value.

problems: when there information changed. combobox isn't updated

option 3 use ibindinglist interface same setup option 2. correct. list changed when remove or add something. problem comboboxes don't change value when specific row changed.

i have @ moment this. datatablecolumnsource

using system; using system.componentmodel; using system.windows.forms;  namespace gui {     public class datatablecolumnsource<t> : ibindinglist     {         public event listchangedeventhandler listchanged;         public datagridview datatable { get; set; }         public int column { get; set; }           public datatablecolumnsource(ref datagridview datatable, int column)         {             this.datatable = datatable;             this.column = column;         }          public void posiblechange(listchangedtype type, int index)         {             if (listchanged != null)             {                 listchanged(this, new listchangedeventargs(type, index));              }         }          public void addindex(propertydescriptor property)         {             throw new notimplementedexception();         }          public object addnew()         {             return new comboboxitem<t>(default(t), -1); ;         }          public bool allowedit         {             { throw new notimplementedexception(); }         }          public bool allownew         {             { return true; }         }          public bool allowremove         {             { throw new notimplementedexception(); }         }          public void applysort(propertydescriptor property, listsortdirection direction)         {             throw new notimplementedexception();         }          public int find(propertydescriptor property, object key)         {             throw new notimplementedexception();         }          public bool issorted         {             { throw new notimplementedexception(); }         }          public void removeindex(propertydescriptor property)         {             throw new notimplementedexception();         }          public void removesort()         {             throw new notimplementedexception();         }          public listsortdirection sortdirection         {             { throw new notimplementedexception(); }         }          public propertydescriptor sortproperty         {             { throw new notimplementedexception(); }         }          public bool supportschangenotification         {             { return true; }         }          public bool supportssearching         {             { return false; }         }          public bool supportssorting         {             { return false; }         }          public int add(object value)         {             throw new notimplementedexception();         }          public void clear()         {             throw new notimplementedexception();         }          public bool contains(object value)         {             throw new notimplementedexception();         }          public int indexof(object value)         {             throw new notimplementedexception();         }          public void insert(int index, object value)         {             throw new notimplementedexception();         }          public bool isfixedsize         {             { throw new notimplementedexception(); }         }          public bool isreadonly         {             { throw new notimplementedexception(); }         }          public void remove(object value)         {             throw new notimplementedexception();         }          public void removeat(int index)         {             throw new notimplementedexception();         }          public object this[int index]         {                         {                 if (this.datatable.rows[index].cells[this.column].value == null)                     return null;                  t w =(t) convert.changetype(this.datatable.rows[index].cells[this.column].value, typeof(t));                 return w;             }             set             {                 throw new notimplementedexception();             }         }          public void copyto(array array, int index)         {             throw new notimplementedexception();         }          public int count         {                         {                 return this.datatable.rows.count -1;             }         }          public bool issynchronized         {             { throw new notimplementedexception(); }         }          public object syncroot         {             { throw new notimplementedexception(); }         }          public system.collections.ienumerator getenumerator()         {             int c = count;             (int = 0; < c; i++)                 yield return this[i];         }     } } 

gui

public partial class frmndfa : form     {          datatablecolumnsource<char> alphabetsource;         datatablecolumnsource<string> statesource;         int lastdeletedindex;          public frmndfa()         {             initializecomponent();              alphabetsource = new datatablecolumnsource<char>(ref this.dgvalphabet, 0);             statesource = new datatablecolumnsource<string>(ref this.dgvstates, 0);              datagridviewcomboboxcolumn column = (datagridviewcomboboxcolumn)this.dgvtransitions.columns[0];             bindingsource clm1bs = new bindingsource();             clm1bs.datasource = statesource;             column.datasource = clm1bs;             column.valuetype = typeof(string);              column = (datagridviewcomboboxcolumn)this.dgvtransitions.columns[1];             bindingsource clm2bs = new bindingsource();             clm2bs.datasource = statesource;             column.datasource = clm2bs;             column.valuetype = typeof(string);              column = (datagridviewcomboboxcolumn)this.dgvtransitions.columns[2];             bindingsource clm3bs = new bindingsource();             clm3bs.datasource = alphabetsource;             column.datasource = clm3bs;             column.valuetype = typeof(char);          }          private void dgvalphabet_userdeletingrow(object sender, datagridviewrowcanceleventargs e)         {             lastdeletedindex = e.row.index;         }          private void dgvalphabet_userdeletedrow(object sender, datagridviewroweventargs e)         {             datagridviewrow row = e.row;             string value = (row.cells[0].value != null)? row.cells[0].value.tostring() : "";              alphabetsource.posiblechange(listchangedtype.itemdeleted, lastdeletedindex);              list<datagridviewrow> removerows = new list<datagridviewrow>();             //update transitions             foreach (datagridviewrow datarow in this.dgvtransitions.rows)             {                 if (datarow.cells[2].value != null && datarow.cells[2].value.tostring().equals(value))                     removerows.add(datarow);             }               foreach(datagridviewrow datarow in removerows)             {                 this.dgvtransitions.rows.remove(datarow);             }         }          private void dgvalphabet_cellendedit(object sender, datagridviewcelleventargs e)         {             if(this.dgvalphabet.rows[e.rowindex].isnewrow)                 alphabetsource.posiblechange(listchangedtype.itemadded, e.rowindex);             else                 alphabetsource.posiblechange(listchangedtype.itemchanged, e.rowindex);          }          private void dgvalphabet_cellvalidating(object sender, datagridviewcellvalidatingeventargs e)         {             e.cancel = e.formattedvalue != null && e.formattedvalue.tostring().length > 1;         }          private void dgvstates_userdeletingrow(object sender, datagridviewrowcanceleventargs e)         {             lastdeletedindex = e.row.index;         }          private void dgvstates_userdeletedrow(object sender, datagridviewroweventargs e)         {             datagridviewrow row = e.row;             string value = (row.cells[0].value != null) ? row.cells[0].value.tostring() : "";             statesource.posiblechange(listchangedtype.itemdeleted, this.dgvstates.rows.indexof(e.row));              list<datagridviewrow> removerows = new list<datagridviewrow>();             //update transitions             foreach (datagridviewrow datarow in this.dgvtransitions.rows)             {                 if (datarow.cells[0].value != null && datarow.cells[0].value.equals(value))                     removerows.add(datarow);                 else if (datarow.cells[1].value != null && datarow.cells[1].value.equals(value))                     removerows.add(datarow);             }              foreach(datagridviewrow datarow in removerows)             {                 this.dgvtransitions.rows.remove(datarow);             }         }          private void dgvstates_cellendedit(object sender, datagridviewcelleventargs e)         {             if (e.columnindex != 0)                 return;             statesource.posiblechange(listchangedtype.itemchanged, e.rowindex);          }     }