[英]How to populate a text box with values from a derived class? C#
在我的表格中,我有以下内容...
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来自ManufacturedProduct类,该类是Product的派生类。 最后一行代码是行不通的。 我希望能够用product1.VendorID中的值填充tbVendorID(顺便说一下,它是一个int)
我收到以下错误... Objects.Product'不包含'VendorID'的定义,并且找不到扩展方法'VendorID'接受类型为'Objects.Product'的第一个参数(是否缺少using指令或组装参考?)
如果要访问子类的属性,则需要将其强制转换为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;
}
您可以执行以下操作:
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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