Ya lo he solucionado,
Lo que he echo ha sido juntar las dos columnas en el select y asi no tengo problemas.
Código vb.net:
Ver originalSql = "select distinct concat(DI,'->',DiDescript) as e from operario order by DI"
Y recojo el valor de esta forma:
Código vb.net:
Ver originalMe.DropDownListS1.DataSource = ds.Tables(0)
Me.DropDownListS1.DataValueField = "e"
Me.DropDownListS1.DataTextField = "e"
Me.DropDownListS1.DataBind()
Me.DropDownListS1.Items.Insert(0, "")
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