在form_load里写上
DataSet DataSet1=new DataSet();
sqlDataAdapter1.Fill(DataSet1);
ComboBox1.DataSource = DataSet1.Tables("Suppliers")
ComboBox1.DisplayMember = "ProductName"
DataSet DataSet1=new DataSet();
sqlDataAdapter1.Fill(DataSet1);
ComboBox1.DataSource = DataSet1.Tables("Suppliers")
ComboBox1.DisplayMember = "ProductName"
comboBox1.DataSource = dataSet11.Tables[0];
comboBox1.DisplayMember = "ProductName";