小编use*_*367的帖子

我坚持这个错误,我检查的值不是null.当我尝试按下"保存"按钮时出现此错误.

请帮帮我,这是错误:

The parameter conversion from type 'System.String' to type 'ULIV.ViewModels.NewProposal' failed because no type converter can convert between these types.

ModelState.IsValid为false.

这是使用的视图模型:

public class PurchaseOrderViewModel
{
    [Key]
    public int ID { get; set; }

    public IEnumerable<Institution> Institution { get; set; }

    [Required]
    public string PurchaseOrderNo { get; set; }

    [Required]
    public DateTime PurchaseOrderDate { get; set; }

    [Required]
    public DateTime ReceivedDate { get; set; }

    public string Remarks { get; set; }

    public IEnumerable<NewProposal> Proposal { get; set; } …