我有一个函数,可以对作为参数传递的DataGridViewRow的单元格之一进行数据绑定.

public static void DataBindCells(DataGridViewRow row)
{
    DataGridViewComboBoxCell priceModes = row.Cells["ColumnPriceMode"] as DataGridViewComboBoxCell;
    priceModes.DataSource = UtilityClass.GetDataTable("SELECT PriceModeID,PriceModeName FROM PriceModes");
    priceModes.DisplayMember = "PriceModeName";
    priceModes.ValueMember = "PriceModeID";
}

使用此功能：
有一个“添加行”按钮,它调用DataBindCells函数.
使用此功能的DataGridView实际上用于填写发票.行的列为：
ItemName,PriceMode,价格,数量,数量.

价格模式是件/公斤/打等.
当用户想要在账单中添加项目时,单击添加行按钮.

问题是执行上述功能时,在DataGridViewComboBoxCell中什么也没有选择.
有什么方法可以让默认情况下的第一个项目被选中.

解决方法:

下面的示例证明DefaultValuesNeeded可以满足您的要求.

…

命名空间WindowsFormsApplication1 {

public static class Helper {
    public static DataTable ToDataTable<T>(this List<T> list) where T : class {
        Type type = typeof ( T );
        var ps = type.GetProperties ( );
        var cols = from p in ps
                   select new DataColumn ( p.Name , p.PropertyType );

        DataTable dt = new DataTable ( );
        dt.Columns.AddRange ( cols.ToArray ( ) );

        list.ForEach ( (l) => {
            List<object> objs = new List<object> ( );
            objs.AddRange ( ps.Select ( p => p.GetValue ( l , null ) ) );
            dt.Rows.Add ( objs.ToArray ( ) );
        } );

        return dt;
    }
}

public enum SendTypes {
    WeiBo ,
    QQ ,
    MSN ,
    EML
}

public class Receiver {
    public string Address {
        get;
        set;
    }
    public SendTypes SendType {
        get;
        set;
    }
    public string Msg {
        get;
        set;
    }
}

public partial class Form1 : Form {
    public Form1() {
        InitializeComponent ( );
    }

    private void SetDataGrid() {
        DataGridViewComboBoxColumn colSendType = new DataGridViewComboBoxColumn ( );
        colSendType.Items.AddRange ( SendTypes.EML, SendTypes.MSN, SendTypes.QQ, SendTypes.WeiBo );
        colSendType.Name = "SendType";

        colSendType.DataPropertyName = "SendType";
        this.dataGridView1.Columns.Add ( colSendType );

        DataGridViewTextBoxColumn colAddress = new DataGridViewTextBoxColumn ( );
        colAddress.Name = "Address";
        colAddress.DataPropertyName = "Address";
        this.dataGridView1.Columns.Add ( colAddress );

        this.dataGridView1.AutoGenerateColumns = false;
        //this.dataGridView1.AllowUserToAddRows = true;
    }

    private void LoadData() {
        var tmp = new Receiver {
            Address = "http://www.weibo.com/?uid=1000",
            SendType = SendTypes.WeiBo,
            Msg = "Test"
        };
        List<Receiver> datas = new List<Receiver>();
        datas.Add(new Receiver {
            Address = "http://www.weibo.com/?uid=1000",
            SendType = SendTypes.WeiBo,
            Msg = "Test"
        });
        datas.Add(new Receiver(){
            Address = "10001",
            SendType = SendTypes.QQ,
            Msg = "test"
        });
        datas.Add(new Receiver(){
            Address = "xling@abc.com",
            SendType = SendTypes.EML,
            Msg = "TEST TEST"
        });

        this.dataGridView1.DataSource = datas;//.ToDataTable();
    }

    private void Form1_Load(object sender , EventArgs e) {
        this.SetDataGrid ( );
        this.LoadData ( );
    }

    private void dataGridView1_DefaultValuesNeeded(object sender , DataGridViewRowEventArgs e) {
        dataGridView1.Rows[e.Row.Index].Cells["SendType"].Value = SendTypes.EML;
    }
}

}