How to update selected items in datagrid ?

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C#

WPF

DataGrid

I develop a WPF application in C # and use EntityFramework. I have a GridView component (which name is dgv_name) and I want to select several lines, then I want to update State column after clicking the btn_Void. The GridView contains three coulmnns which are:

ID (int)
Name (string (MaxLength 50))
State (boolean)
I want to change value of State from true to false for all the selected lines when I click the btn_void. My code:

What I have tried:

private void btn_Void_ItemClick(object sender, DevExpress.Xpf.Bars.ItemClickEventArgs e)
    { 
      foreach (DataGridCellInfo cell in dgv_name.SelectedItems)
        {
            //I dont know what code should i write
        }
    }