How to retrieve data from datagrid combo box using wpf ?

See more:

XAML

WPF

C#3.5

C#5.0

Hi actually i am a newbie to the wpf and here i am facing a problem . I unable to retrieve values or data from data grid using a combo box and when ever i am trying to retrieve im getting a error "Object set to an instance" here is my code please check and help is appreciated


//XAML code :

<datagridcomboboxcolumn header="packagetype2" textbinding="{Binding Uom}" x:name="cmb_pktype" xmlns:x="#unknown">


//c# code:


DataSet ds1 = uomc.fillcombo();

cmb_pktype.ItemsSource = ds1.Tables[0].DefaultView;
cmb_pktype.DisplayMemberPath = ds1.Tables[0].Columns["Name"].ToString();
cmb_pktype.SelectedValuePath = ds1.Tables[0].Columns["Id"].ToString();



//when i am retrieveing the data like as below


string type = (dgv_uomconversionmapping.SelectedCells[1].Column.GetCellContent(dgv_uomconversionmapping.Items[i]) as TextBlock).Text;


//This retrieving process is working for data grid textblock column
//as this way how can i read the datagrid combobox column