Selecting in comboBox

Select Cob  by  input value 

this.cobTest.DataSource = dv; this.cobTest.ValueMember = "TrainingHeaderKey"; this.cobTest.DisplayMember = "TrainingCode"; this.cobTest.DropDownStyle = System.Windows.Forms.ComboBoxStyle.DropDown; this.cobTest.AutoCompleteMode = AutoCompleteMode.SuggestAppend; this.cobTest.AutoCompleteSource = AutoCompleteSource.ListItems;