[英]How to populate a text box with values from a derived class? C#
在我的表格中,我有以下內容...
if (productNo == this.product1.ProductNumber) //ProductNumber comes from Product class
{
//if so, set the other values of the text boxes to that of the
//product in memory
tbDescription.Text = product1.ProductDescription; //Works - from Product class
tbOnHand.Text = product1.NumberOnHand.ToString(); //Works - from Product class
tbUnitOfMeasure.Text = product1.UnitOfMeasure; //Works - from Product class
tbVendorID.Text = product1.VendorID; // Doesn't work - from derived ManufacturedProduct class
}
其中VendorID來自ManufacturedProduct類,該類是Product的派生類。 最后一行代碼是行不通的。 我希望能夠用product1.VendorID中的值填充tbVendorID(順便說一下,它是一個int)
我收到以下錯誤... Objects.Product'不包含'VendorID'的定義,並且找不到擴展方法'VendorID'接受類型為'Objects.Product'的第一個參數(是否缺少using指令或組裝參考?)
如果要訪問子類的屬性,則需要將其強制轉換為ManufacturedProduct
:
ManufacturedProduct mfgProduct = (ManufacturedProduct) product1;
if (productNo == mfgProduct.ProductNumber)
{
tbDescription.Text = mfgProduct.ProductDescription;
tbOnHand.Text = mfgProduct.NumberOnHand.ToString();
tbUnitOfMeasure.Text = mfgProduct.UnitOfMeasure;
tbVendorID.Text = mfgProduct.VendorID;
}
您可以執行以下操作:
if (productNo == this.product1.ProductNumber) //ProductNumber comes from Product class
{
tbDescription.Text = product1.ProductDescription;
tbOnHand.Text = product1.NumberOnHand.ToString();
tbUnitOfMeasure.Text = product1.UnitOfMeasure;
if(priduct1 is ManufacturedProduct)
tbVendorID.Text = ((ManufacturedProduct)product1).VendorID.ToString();
}
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