尝试关键字导致问题 [英] try keyword causing problems
问题描述
我有一些代码，我试图将其包含在try / catch块中。这个
代码在.aspx页面的代码隐藏的Page_Load（）方法中。
在尝试的行上关键字是，我收到错误对象
引用未设置为对象的实例。为什么我会在
上得到尝试关键词。我已经复制了下面的代码，你可以看到我已经用b $ b注释了额外的代码，我所拥有的只是
Page_Load（ ）事件和try / catch块。可能导致这种情况的原因是什么？
public void Page_Load（object sender，System.EventArgs e）
{
// string sSQL;
试试
{
/ *
OleDbConnection2.Open（）;
sSQL =" SELECT Statement_Id，Statement_In_Brief FROM Statements" ;;
daStatements = new OleDbDataAdapter（sSQL，OleDbConnection1）;
daStatements.Fill（dsStatements）;
Response.Write（" Record count = " +
dsStatements.Tables [0] .Rows.Count.ToString（））;
string sSQL =" SELECT Statement_Id，Statement_In_Brief FROM Statements" ;;
daStatements = new OleDbDataAdapter（sSQL，OleDbConnection1）;
daStatements.Fill（dsStatements，" Statements"）;
DropDownList1.DataSource = dsStatements.Tables [" Statements"];
DropDownList1.DataTextField =" State ment_In_Brief" ;;
DropDownList1.DataValueField =" Statement_ID";
DropDownList1.DataBind（）;
Response.Write（" test"）;
OleDbConnection1.Close（）;
* /
}
catch（例外e）
{
//回复.Write（e.ToString）;
}
} //结束Page_Load（）事件
I''ve got some code that I''m trying to enclose in a try/catch block. This
code is in the Page_Load() method of the code-behind for an .aspx page.
On the line where the "try" keyword is, I''m getting the error "Object
reference is not set to an instance of an object". Why would I get that on
the "try" keyword. I''ve copied the code below, and you can see that I''ve
commented out the extra code to the point where all I have is the
Page_Load() event and the try/catch block. What could be causing this?
public void Page_Load(object sender, System.EventArgs e)
{
//string sSQL;
try
{
/*
OleDbConnection2.Open();
sSQL = "SELECT Statement_Id,Statement_In_Brief FROM Statements";
daStatements = new OleDbDataAdapter(sSQL,OleDbConnection1);
daStatements.Fill(dsStatements);
Response.Write( "Record count = " +
dsStatements.Tables[0].Rows.Count.ToString());
string sSQL = "SELECT Statement_Id,Statement_In_Brief FROM Statements";
daStatements = new OleDbDataAdapter(sSQL,OleDbConnection1);
daStatements.Fill(dsStatements,"Statements");
DropDownList1.DataSource = dsStatements.Tables["Statements"];
DropDownList1.DataTextField = "Statement_In_Brief";
DropDownList1.DataValueField = "Statement_ID";
DropDownList1.DataBind();
Response.Write("test");
OleDbConnection1.Close();
*/
}
catch(Exception e)
{
//Response.Write(e.ToString);
}
} // end Page_Load() event
推荐答案
你好，
你确定在调用之前实例化了OleDbConnection2
Open（）方法？
如果是，那么检查你正在使用的UI元素是否相同 - 我怀疑
问题与他们有关，但是 - 他们应该由InitializeComponent（）方法中的
设计器初始化。
所以 - 检查是否正在初始化OleDbConnection2 var。或者只是在它上面添加一个
额外的行 - 类似于：
OleDbConnection2 = new OleDbConnection（[connectionstring goes here]）;
干杯，
Branimir
-
Branimir Giurov
MCSD.NET，MCDBA，MCT
eAgility LLC
" Curt Emich" < CE **** @ comcast.net>在消息中写道
news：3f ******************** @ comcast.com ...
Hi there,
are you sure that the OleDbConnection2 is being instantiated before calling
the Open() method?
If "Yes", then check the same for the UI elements you''re using - i doubt
that the problem is with them , though - they should be initialized by the
designer inside the InitializeComponent() method.
So - check if the OleDbConnection2 var is being initialized. Or just put an
extra line on top of it - something like:
OleDbConnection2 = new OleDbConnection(["connectionstring goes here"]);
Cheers,
Branimir
--
Branimir Giurov
MCSD.NET, MCDBA, MCT
eAgility LLC
"Curt Emich" <ce****@comcast.net> wrote in message
news:3f********************@comcast.com...
I我有一些代码，我试图将其包含在try / catch块中。这个代码位于.aspx页面的代码隐藏的Page_Load（）方法中。
在尝试的行上关键字是，我得到错误对象
引用未设置为对象的实例。为什么我会在尝试中获得
关键词。我已经复制了下面的代码，你可以看到我已经将额外的代码注释掉了，我所拥有的只是
Page_Load（）事件和try / catch块。可能导致这种情况的原因是什么？
public void Page_Load（object sender，System.EventArgs e）
//字符串sSQL;
尝试
/ *
OleDbConnection2.Open（）;
sSQL = SELECT Statement_Id，Statement_In_Brief FROM Statements;
daStatements = new OleDbDataAdapter（sSQL，OleDbConnection1）;
daStatements.Fill（dsStatements）;
Response.Write（" Record count =" +
dsStatements.Tables [0] .Rows.Count.ToString（））;
string sSQL =" SELECT Statement_Id，Statement_In_Brief FROM Statements" ;;
daStatements = new OleDbDataAdapter（sSQL，OleDbConnection1）;
daStatements.Fill（dsStatements，" Statements"）;
DropDownList1.DataSource = dsStatements.Tables [" Statements"];
DropDownList1.DataTextField =" Statement_In_Brief";
DropDownList1.DataValueField =" Statement_ID" ; ;
DropDownList1.DataBind（）;
Response.Write（" test"）;
OleDbConnection1.Close（）;
* /
}抓住（例外e）
//响应。写（e.ToString）;
}
} //结束Page_Load（）事件
I''ve got some code that I''m trying to enclose in a try/catch block. This
code is in the Page_Load() method of the code-behind for an .aspx page.
On the line where the "try" keyword is, I''m getting the error "Object
reference is not set to an instance of an object". Why would I get that on the "try" keyword. I''ve copied the code below, and you can see that I''ve
commented out the extra code to the point where all I have is the
Page_Load() event and the try/catch block. What could be causing this?
public void Page_Load(object sender, System.EventArgs e)
{
//string sSQL;
try
{
/*
OleDbConnection2.Open();
sSQL = "SELECT Statement_Id,Statement_In_Brief FROM Statements";
daStatements = new OleDbDataAdapter(sSQL,OleDbConnection1);
daStatements.Fill(dsStatements);
Response.Write( "Record count = " +
dsStatements.Tables[0].Rows.Count.ToString());
string sSQL = "SELECT Statement_Id,Statement_In_Brief FROM Statements";
daStatements = new OleDbDataAdapter(sSQL,OleDbConnection1);
daStatements.Fill(dsStatements,"Statements");
DropDownList1.DataSource = dsStatements.Tables["Statements"];
DropDownList1.DataTextField = "Statement_In_Brief";
DropDownList1.DataValueField = "Statement_ID";
DropDownList1.DataBind();
Response.Write("test");
OleDbConnection1.Close();
*/
}
catch(Exception e)
{
//Response.Write(e.ToString);
}
} // end Page_Load() event
" Curt Emich" < CE **** @ comcast.net>写在
新闻：3f ******************** @ comcast.com：
"Curt Emich" <ce****@comcast.net> wrote in
news:3f********************@comcast.com:
我有一些代码，我试图将其包含在try / catch
块中。此代码位于.aspx页面的代码隐藏的Page_Load（）方法中。
在尝试的行上关键字是，我收到错误
对象引用未设置为对象的实例。为什么
我会在尝试中得到它关键词。我已经复制了下面的代码
，你可以看到我已经注释了额外的代码，以便我所拥有的是Page_Load（）事件和
try / catch块。可能导致这种情况的原因是什么？
I''ve got some code that I''m trying to enclose in a try/catch
block. This code is in the Page_Load() method of the
code-behind for an .aspx page.
On the line where the "try" keyword is, I''m getting the error
"Object reference is not set to an instance of an object". Why
would I get that on the "try" keyword. I''ve copied the code
below, and you can see that I''ve commented out the extra code to
the point where all I have is the Page_Load() event and the
try/catch block. What could be causing this?
Curt，
只是为了澄清：尝试的例外情况正在发生关键字甚至
所有其他代码被注释掉了吗？
如果是这种情况，如果你使用的是Visual Studio 2002，那么' VS2002中的
a bug，当发生异常时，调试器会突出显示错误的行
。 MSDN上有补丁。
如果您没有使用VS2002，请提供更多信息：
- 。网络版
- 你正在使用哪个IDE（VS2003，SharpDevelop等）
- Windows版本
- 一个小的完整代码示例演示这个问题，或者如果不可能的话，那就是
，然后展开你发布的代码片段
，这样它就包含了之前和之后的更多代码
发生异常的地方。
希望这会有所帮助。
克里斯。
---- ---------
CR Timmons Consulting，Inc。
http://www.crtimmonsinc.com/
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