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MessageBox.Show("for loop, last row..."); //TEST CODE问题 - 行执行后出现错误。可能是什么原因 ？当我从另一个数据库中获取我的结果集时，就没有这样的问题。：（ 我该如何解决 ？

代码 -

    public void Main()
    {

        OleDbDataAdapter oleDA = new OleDbDataAdapter();
        DataTable dt = new DataTable();
        DataColumn col = null;
        DataRow row = null;
        string strCols = "";

        oleDA.Fill(dt, Dts.Variables["MyResultSet"].Value);
        col = dt.Columns["MyColumn"];

        int lastIdx = dt.Rows.Count - 1;

        MessageBox.Show("int declared, for loop..."); //TEST CODE

        //loop upto 2nd last data row
        for (int i = 0; i <= lastIdx-1; i++)
        {
            row = dt.Rows[i];
            strCols += row[col.Ordinal].ToString() + ", ";
        }

        MessageBox.Show("for loop, last row..."); //TEST CODE

        row = dt.Rows[lastIdx];
        strCols += row[col.Ordinal].ToString(); //!!! I GET ERROR HERE !

        MessageBox.Show("strCols");

        Dts.TaskResult = (int)ScriptResults.Success;

    }

错误 -

Error: System.Reflection.TargetInvocationException: Exception has been thrown by the target of an invocation. ---> System.IndexOutOfRangeException: There is no row at position -1.
   at System.Data.RBTree`1.GetNodeByIndex(Int32 userIndex)
   at System.Data.RBTree`1.get_Item(Int32 index)
   at System.Data.DataRowCollection.get_Item(Int32 index)
   at My-Long-Code-Goes-Here.csproj.ScriptMain.Main()
   --- End of inner exception stack trace ---
   at System.RuntimeMethodHandle._InvokeMethodFast(Object target, Object[] arguments, SignatureStruct& sig, MethodAttributes methodAttributes, RuntimeTypeHandle typeOwner)
   at System.Reflection.RuntimeMethodInfo.Invoke(Object obj, BindingFlags invokeAttr, Binder binder, Object[] parameters, CultureInfo culture, Boolean skipVisibilityChecks)
   at System.Reflection.RuntimeMethodInfo.Invoke(Object obj, BindingFlags invokeAttr, Binder binder, Object[] parameters, CultureInfo culture)
   at System.RuntimeType.InvokeMember(String name, BindingFlags bindingFlags, Binder binder, Object target, Object[] providedArgs, ParameterModifier[] modifiers, CultureInfo culture, String[] namedParams)
   at Microsoft.SqlServer.Dts.Tasks.ScriptTask.VSTATaskScriptingEngine.ExecuteScript()
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2 回答 2

1

您正在尝试DataTable用一个没有与之关联的命令对象的采用者来填充您，这就是您得到空结果的原因。您需要创建一个命令对象，然后创建相关的DataAdapater然后使用Fill方法，例如：

OleDbCommand selectCommand = new OleDbCommand("select * from yourTable", yourConnection);
OleDbDataAdapter oleDA = new OleDbDataAdapter(selectCommand);
于 2013-10-22T20:38:50.917 回答
1

我猜您的查询没有返回任何行。

检查dt.Rows.Count，确认它 > 0。

于 2013-10-22T20:33:10.210 回答