积极答复者
並未將物件參考設定為物件的執行個體

问题
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public void PSBM()
{string GetBC = DBHelper.ExecuteQuery("select SortCode from Sort where indexid=" + Convert.ToInt32(DropDownList1.SelectedValue));
string GetMC = DBHelper.ExecuteQuery("select SortCode from Sort where indexid=" + Convert.ToInt32(DropDownList2.SelectedValue));
string GetSC = DBHelper.ExecuteQuery("select SortCode from Sort where indexid=" + Convert.ToInt32(DropDownList3.SelectedValue));if ((GetBC != "") && (GetMC != ""))
{
string sqlPSBM = "select * from PSBM where BClass='" + GetBC + "' and MClass='" + GetMC + "' and SClass='" + GetSC + "'";
DataTable dt = SQLOperate.GetTable(sqlPSBM);Equ_name.DataTextField = "ProductName";
Equ_name.DataValueField = "Prod_NameCode";
Equ_name.DataSource = dt.DefaultView;
Equ_name.DataBind();
DBHelper.SetDDLControlTipMsg(Equ_name);
string sqlStandard = "select * from PSBM where BClass='" + GetBC + "' and MClass='" + GetMC + "' and SClass='" + GetSC + "' and Prod_NameCode='" + Equ_name.SelectedItem.Value + "'";
DataTable sS = SQLOperate.GetTable(sqlStandard);Type_Size.DataTextField = "Standard";
Type_Size.DataValueField = "StandardCode";
Type_Size.DataSource = sS.DefaultView;
Type_Size.DataBind();
DBHelper.SetDDLControlTipMsg(Type_Size);
string sqlBrand = "select * from PSBM where BClass='" + GetBC + "' and MClass='" + GetMC + "' and SClass='" + GetSC + "' and Prod_NameCode='" + Equ_name.SelectedItem.Value + "' and StandardCode='" + Type_Size.SelectedItem.Value + "'";
DataTable sB = SQLOperate.GetTable(sqlBrand);Brand.DataTextField = "Brand";
Brand.DataValueField = "BrandCode";
Brand.DataSource = sB.DefaultView;
Brand.DataBind();
DBHelper.SetDDLControlTipMsg(Brand);
string sqlMadeArea = "select * from PSBM where BClass='" + GetBC + "' and MClass='" + GetMC + "' and SClass='" + GetSC + "' and Prod_NameCode='" + Equ_name.SelectedItem.Value + "' and StandardCode='" + Type_Size.SelectedItem.Value + "' and BrandCode='" + Brand.SelectedItem.Value + "'";
DataTable sM = SQLOperate.GetTable(sqlMadeArea);MadeArea.DataTextField = "MadeArea";
MadeArea.DataValueField = "MadeAreaCode";
MadeArea.DataSource = sM.DefaultView;
MadeArea.DataBind();
DBHelper.SetDDLControlTipMsg(MadeArea);
}
}
执行到这一句就抱错了,始终找不到原因。("string sqlStandard = "select * from PSBM where BClass='" + GetBC + "' and MClass='" + GetMC + "' and SClass='" + GetSC + "' and Prod_NameCode='" + Equ_name.SelectedItem.Value + "'";
"),大伙帮忙看下。
答案
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dear
只能设定断点检查有哪个变量是null,也很有可能是SQL语句错误,导致有SQL 变量为null
秘訣無它,唯勤而已 http://www.dotblogs.com.tw/yc421206/- 已标记为答案 Leo Liu - MSFTModerator 2011年10月3日 2:19
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Hi Tommy,
如果我没有想错的话这个错误就是"未将对象引用设置到对象的实例"这个错误.
在你代码的出错行里面也只有Equ_name.SelectedItem可能出这个错.
在这一行之后设一个断点然后看看Equ_name.SelectedItem是不是值为null. 如果是,再检查你的Equ_name控件相关的代码是否有问题.
祝你快乐每一天,
Leo Liu [MSFT]
MSDN Community Support | Feedback to us
Get or Request Code Sample from Microsoft
Please remember to mark the replies as answers if they help and unmark them if they provide no help.
- 已编辑 Leo Liu - MSFTModerator 2011年9月29日 8:03
- 已标记为答案 Leo Liu - MSFTModerator 2011年10月3日 2:19
全部回复
-
dear
只能设定断点检查有哪个变量是null,也很有可能是SQL语句错误,导致有SQL 变量为null
秘訣無它,唯勤而已 http://www.dotblogs.com.tw/yc421206/- 已标记为答案 Leo Liu - MSFTModerator 2011年10月3日 2:19
-
Hi Tommy,
如果我没有想错的话这个错误就是"未将对象引用设置到对象的实例"这个错误.
在你代码的出错行里面也只有Equ_name.SelectedItem可能出这个错.
在这一行之后设一个断点然后看看Equ_name.SelectedItem是不是值为null. 如果是,再检查你的Equ_name控件相关的代码是否有问题.
祝你快乐每一天,
Leo Liu [MSFT]
MSDN Community Support | Feedback to us
Get or Request Code Sample from Microsoft
Please remember to mark the replies as answers if they help and unmark them if they provide no help.
- 已编辑 Leo Liu - MSFTModerator 2011年9月29日 8:03
- 已标记为答案 Leo Liu - MSFTModerator 2011年10月3日 2:19