我正在尝试为一个项目编码，但不断出现无效的特定转换错误。任何人都可以帮助我，因为我很难过。提前致谢。
Server Error in '/c#project' Application.
Specified cast is not valid.
Description: An unhandled exception occurred during the execution of the current web request. Please review the stack trace for more information about the error and where it originated in the code.
Exception Details: System.InvalidCastException: Specified cast is not valid.
Source Error:
Line 39: cmd.Parameters.Add("@ProductId", OleDbType.Char).Value = strProductId;
Line 40: object oQty = cmd.ExecuteScalar();
Line 41: int intQuantityOnHand = (int)oQty;
Line 42: mDB.Close();
Line 43: int intBuyQuantity = int.Parse(ddlQty.Items[ddlQty.SelectedIndex].ToString());
Source File: c:\Users\jacob\Desktop\c#project\ProductDetails.aspx.cs Line: 41
Stack Trace:
[InvalidCastException: Specified cast is not valid.]
ProductDetails.btnBuy_Click(Object sender, EventArgs e) in c:\Users\jacob\Desktop\c#project\ProductDetails.aspx.cs:41
System.Web.UI.WebControls.Button.OnClick(EventArgs e) +118
System.Web.UI.WebControls.Button.RaisePostBackEvent(String eventArgument) +112
System.Web.UI.WebControls.Button.System.Web.UI.IPostBackEventHandler.RaisePostBackEvent(String eventArgument) +10
System.Web.UI.Page.RaisePostBackEvent(IPostBackEventHandler sourceControl, String eventArgument) +13
System.Web.UI.Page.RaisePostBackEvent(NameValueCollection postData) +36
System.Web.UI.Page.ProcessRequestMain(Boolean includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint) +5563
Version Information: Microsoft .NET Framework Version:4.0.30319; ASP.NET Version:4.0.30319.272
最佳答案
第 41 行:显然 oQty 不能转换为 Int32 。尝试
int intQuantityOnHand = Convert.ToInt32(oQty);
关于c# - "Specified cast is not valid"转换 ExecuteScalar 的结果，我们在Stack Overflow上找到一个类似的问题：https://stackoverflow.com/questions/11089939/