Question

又一个wpf问题。

我有两个采用十进制值的DataGridTextColumn。出于某种原因，当我添加一个新行（列的初始值为零）时，我必须在这两列中的任何一列中输入两次值。我第一次在其中输入一个值并标签，该值返回零。在我第二次输入值之后。

<DataGridTextColumn Header="Unit Price" EditingElementStyle="{StaticResource CellEditStyle}" Width="SizeToCells" MinWidth="90" Binding="{Binding ItemUnitPrice, Mode=TwoWay, UpdateSourceTrigger=PropertyChanged, ValidatesOnDataErrors=True}" />
<DataGridTextColumn Header="Qty" EditingElementStyle="{StaticResource CellEditStyle}" Width="SizeToCells" MinWidth="65" Binding="{Binding ItemQty, Mode=TwoWay, UpdateSourceTrigger=PropertyChanged, ValidatesOnDataErrors=True}" />

dg与我的vm中的可观察集合绑定。我不确定它与它有什么关系，但是我通过创建一个单独的类（用于在用户离开行时保存数据）向我的OC添加了一个endit事件：

public class ObservableProjectExpenseItems : ObservableCollection<ProjectExpenseItemsBO>
{
    protected override void InsertItem(int index, ProjectExpenseItemsBO item)
    {
        base.InsertItem(index, item);
        item.ItemEndEdit += new ProjectExpenseItemsBO.ItemEndEditEventHandler((x) =>
        {
            if (ItemEndEdit != null)
                ItemEndEdit(x);
        });
    }

    public event ProjectExpenseItemsBO.ItemEndEditEventHandler ItemEndEdit;
}

我的业务对象如下所示：

public class ProjectExpenseItemsBO : IDataErrorInfo, IEditableObject
{
    public int RowID { get; set; }
    public int ProjectExpenseID { get; set; }
    public string ItemNumber { get; set; }
    public string ItemDescription { get; set; }
    public decimal ItemUnitPrice { get; set; }
    public decimal ItemQty { get; set; }
    public string SupplierName { get; set; }
    public DateTime CreateDate { get; set; }

    public ProjectExpenseItemsBO()
    {

    }
   // string method
    static bool IsStringMissing(string value)
    {
        return String.IsNullOrEmpty(value) || value.Trim() == String.Empty;
    }

    private bool _isValid = true;
    public bool IsValid 
    {
        get { return _isValid; }
        set { _isValid = value; }
    }

    #region IDataErrorInfo Members

    public string Error
    {
        get
        {
            return this[string.Empty];
        }
    }

    public string this[string propertyName]
    {
        get
        {
            string result = string.Empty;
            if (propertyName == "ProjectExpenseID")
            {
                if (this.ProjectExpenseID == 0)
                    result = "An existing project expense item must be selected!";
            }

            if (propertyName == "ItemNumber")
            {
                if (this.ItemNumber != null)
                {
                    if (IsStringMissing(this.ItemNumber))
                        result = "Item number cannot be empty!";
                    if (this.ItemNumber.Length > 50)
                        result = "Item number cannot be longer than 50 characters!";
                }
            }

            if (propertyName == "ItemDescription")
            {
                if (this.ItemDescription != null)
                {
                    if (this.ItemDescription.Length > 256)
                        result = "Item description cannot be longer than 256 characters!";
                }
            }

            if (propertyName == "ItemUnitPrice")
            {
                if (this.ItemUnitPrice == 0.0M)
                    result = "Item unit price cannot be empty!";
            }

            if (propertyName == "ItemQty")
            {
                if (this.ItemQty == 0.0M)
                    result = "Item quantity cannot be empty!";
            }

            if (propertyName == "SupplierName")
            {
                if (this.SupplierName != null)
                {
                    if (this.SupplierName.Length > 128)
                        result = "Item number cannot be longer than 128 characters!";
                }
            }

            if (result.Length > 0)
                IsValid = false;
            else
                IsValid = true;

            return result;
        }
    }

    #endregion

    #region IEditableObject Members

    public delegate void ItemEndEditEventHandler(IEditableObject sender);

    public event ItemEndEditEventHandler ItemEndEdit;

    public void BeginEdit()
    {
        //throw new NotImplementedException();
    }

    public void CancelEdit()
    {
        //throw new NotImplementedException();
    }

    public void EndEdit()
    {
        if (ItemEndEdit != null)
        {
            ItemEndEdit(this);
        }
    }

    #endregion
}

}

Answer 1

这在技术上不是答案，但我发现问题如下：

        if (propertyName == "ItemQty") 
        { 
            if (this.ItemQty == 0.0M) 
                result = "Item quantity cannot be empty!"; 
        }

这在新行上总是会失败，因为dg列的默认值为零。一旦我摆脱了这个检查，问题就消失了。

但是，我也遇到了必填字段的问题。验证过程（IDataError）会触发您输入新行的第二行。显然，大多数验证都会因为您尚未输入数据而失败。当您输入初始值时，即使它是合法的，该值也会被清除。我不认为这是正确的行为，并想知道是否有办法关闭初始验证，直到用户离开datagrid行。除此之外，我不确定为什么会被清除。它只在输入初始值时发生。一旦您退出并重新登录，您就可以输入一个值，它会保留，有效与否。如果无效，验证样式将标记无效列。

wpf datagrid中绑定十进制值的问题

1 个答案: