當使用xpath爲xml添加元素時，對象引用未設置爲對象的實例

我有一個xml文件，並且想要將一個子元素添加到其中一個節點，不知道xpath爲什麼會拋出null異常。這當然是因爲我可能給錯誤的xpath值。會是什麼XPath的添加元素在這裏：當使用xpath爲xml添加元素時，對象引用未設置爲對象的實例

的XPath我使用：

//SESSIONANALYSER/KER/MODES/NI/STATEINFORMATION[@TYPE='PREPAID']/INIT/INPUT

這裏就是我想補充的子元素：

<KER> 
    <MODES> 
     <NI> 
     <STATEINFORMATION TYPE="PREPAID"> 
      <INIT INVALIDINPUTRESPONSE="-2"> 
      <INPUT VALUE="LP6ACTIVATION"> 
      **<I have to add a child element here>**

在

以下xml：

<SESSIONANALYSER> 
    <AP> 
    <MODES> 
     <NI> 
     <STATEINFORMATION TYPE="PREPAID"> 
      <INIT INVALIDINPUTRESPONSE="-2"> 
      <INPUT VALUE="SLN7ACTIVATION"> 
       <METHOD NAME="CHECKSUBSCRIBERBALANCE" PARAMETERS="SLN7" POSSIBLEACTIONS="FALLOUTON_FAILUREREGION_SETPSOFAILED_FALSE" MAINTAINSESSION="NO" RESPONSE="-4" NEXTLEVEL="" /> 
       <METHOD NAME="SETPSOINUCIP" PARAMETERS="SLN7" POSSIBLEACTIONS="FALLOUTON_FAILUREREGION_SETPSOFAILED_FALSE" MAINTAINSESSION="NO" RESPONSE="-4" NEXTLEVEL="" /> 
       <METHOD NAME="SENDMESSAGE" PARAMETERS="" POSSIBLEACTIONS="FALLOUTONSUCCESS" MAINTAINSESSION="NO" RESPONSE="0" NEXTLEVEL="" /> 
      </INPUT> 
      <INPUT VALUE="SLN7DEACTIVATION"> 
       <METHOD NAME="UNSETPSOINUCIP" PARAMETERS="SLN7" POSSIBLEACTIONS="FALLOUTON_FAILUREREGION_SETPSOFAILED_FALSE" MAINTAINSESSION="NO" RESPONSE="-4" NEXTLEVEL="" /> 
       <METHOD NAME="jk" PARAMETERS="k" POSSIBLEACTIONS1="k" MAINTAINSESSION="h" RESPONSE="l" NEXTLEVEL=";"></METHOD> 
       <METHOD NAME="SENDMESSAGE" PARAMETERS="23" POSSIBLEACTIONS1="FALLOUTONSUCCESS" MAINTAINSESSION="yes" RESPONSE="format" NEXTLEVEL="msdfm"></METHOD> 
       <METHOD NAME="payments" PARAMETERS="parametervalue" POSSIBLEACTIONS1="fg,f" MAINTAINSESSION="fdjfg89" RESPONSE="ndfgm" NEXTLEVEL="msdfm"></METHOD> 
       <METHOD NAME="payments" PARAMETERS="l" POSSIBLEACTIONS1="l" MAINTAINSESSION="l" RESPONSE="l" NEXTLEVEL="l"></METHOD> 
       <METHOD NAME="payments" PARAMETERS="l" POSSIBLEACTIONS1="l" MAINTAINSESSION="l" RESPONSE="l" NEXTLEVEL="l"></METHOD> 
       <METHOD NAME="payments" PARAMETERS="k" POSSIBLEACTIONS1="k" MAINTAINSESSION="k" RESPONSE="k" NEXTLEVEL="k"></METHOD> 
       <METHOD NAME="payments" PARAMETERS="L" POSSIBLEACTIONS1="L" MAINTAINSESSION="L" RESPONSE="L" NEXTLEVEL="L"></METHOD> 
       <METHOD NAME="SENDMESSAGE" PARAMETERS="23" POSSIBLEACTIONS1="FALLOUTONSUCCESS" MAINTAINSESSION="yes" RESPONSE="format" NEXTLEVEL="msdfm"></METHOD> 
       <METHOD NAME="payments" PARAMETERS="12" POSSIBLEACTIONS1="FALLOUTONSUCCESS" MAINTAINSESSION="yes" RESPONSE="format" NEXTLEVEL="msvm"></METHOD> 
       <METHOD NAME="SENDMESSAGE" PARAMETERS="23" POSSIBLEACTIONS1="FALLOUTONSUCCESS" MAINTAINSESSION="yes" RESPONSE="0" NEXTLEVEL="3"></METHOD> 
       <METHOD NAME="SENDMESSAGE" PARAMETERS="23" POSSIBLEACTIONS1="FALLOUTONSUCCESS" MAINTAINSESSION="NO" RESPONSE="format" NEXTLEVEL="3"></METHOD> 
      </INPUT> 
      </INIT> 
      <FAILUREREGION INVALIDINPUTRESPONSE="-2"> 
      <INPUT VALUE="LOWBALANCE"> 
       <METHOD NAME="SENDMESSAGE" PARAMETERS="" POSSIBLEACTIONS="FALLOUTONSUCCESS" MAINTAINSESSION="NO" RESPONSE="1" NEXTLEVEL="" /> 
      </INPUT> 
      <INPUT VALUE="SETPSOFAILED"> 
       <METHOD NAME="SENDMESSAGE" PARAMETERS="" POSSIBLEACTIONS="FALLOUTONSUCCESS" MAINTAINSESSION="NO" RESPONSE="2" NEXTLEVEL="" /> 
      </INPUT> 
      <INPUT VALUE="UCIPDEBIT"> 
       <METHOD NAME="UNSETPSOINMINSAT" PARAMETERS="SLN7" POSSIBLEACTIONS="FALLOUTON_FAILUREREGION_UNSETPSO_FALSE" MAINTAINSESSION="NO" RESPONSE="-6" NEXTLEVEL="" /> 
       <METHOD NAME="SENDMESSAGE" PARAMETERS="" POSSIBLEACTIONS="FALLOUTONSUCCESS" MAINTAINSESSION="NO" RESPONSE="3" NEXTLEVEL="" /> 
      </INPUT> 
      <INPUT VALUE="UNSETPSO"> 
       <METHOD NAME="SENDMESSAGE" PARAMETERS="" POSSIBLEACTIONS="FALLOUTONSUCCESS" MAINTAINSESSION="NO" RESPONSE="4" NEXTLEVEL="" /> 
      </INPUT> 
      </FAILUREREGION> 
     </STATEINFORMATION> 
     <STATEINFORMATION TYPE="POSTPAID"> 
      <INIT INVALIDINPUTRESPONSE="-2"> 
      <INPUT VALUE="SLN7DEACTIVATION"> 
       <METHOD NAME="SENDMESSAGE" PARAMETERS="" POSSIBLEACTIONS="FALLOUTONSUCCESS" MAINTAINSESSION="NO" RESPONSE="5" NEXTLEVEL="" /> 
      </INPUT> 
      </INIT> 
     </STATEINFORMATION> 
     </NI> 
    </MODES> 
    </AP> 
    <TN> 
    <MODES> 
     <NI> 
     <STATEINFORMATION TYPE="PREPAID"> 
      <INIT INVALIDINPUTRESPONSE="-2"> 
      <INPUT VALUE="LPC16ACTIVATION"> 
       <METHOD NAME="SETPSOINUCIP" PARAMETERS="LPC16" POSSIBLEACTIONS="FALLOUTON_FAILUREREGION_SETPSOFAILED_FALSE" MAINTAINSESSION="NO" RESPONSE="-4" NEXTLEVEL="" /> 
       <METHOD NAME="SENDMESSAGE" PARAMETERS="" POSSIBLEACTIONS="FALLOUTONSUCCESS" MAINTAINSESSION="NO" RESPONSE="0" NEXTLEVEL="" /> 
      </INPUT> 
      <INPUT VALUE="LP26ACTIVATION"> 
       <METHOD NAME="SETPSOINUCIP" PARAMETERS="LP26" POSSIBLEACTIONS="FALLOUTON_FAILUREREGION_SETPSOFAILED_FALSE" MAINTAINSESSION="NO" RESPONSE="-4" NEXTLEVEL="" /> 
       <METHOD NAME="SENDMESSAGE" PARAMETERS="" POSSIBLEACTIONS="FALLOUTONSUCCESS" MAINTAINSESSION="NO" RESPONSE="0" NEXTLEVEL="" /> 
      </INPUT> 
      <INPUT VALUE="LP49ACTIVATION"> 
       <METHOD NAME="SETPSOINUCIP" PARAMETERS="LP49" POSSIBLEACTIONS="FALLOUTON_FAILUREREGION_SETPSOFAILED_FALSE" MAINTAINSESSION="NO" RESPONSE="-4" NEXTLEVEL="" /> 
       <METHOD NAME="SENDMESSAGE" PARAMETERS="" POSSIBLEACTIONS="FALLOUTONSUCCESS" MAINTAINSESSION="NO" RESPONSE="0" NEXTLEVEL="" /> 
      </INPUT> 
      <INPUT VALUE="LPT16ACTIVATION"> 
       <METHOD NAME="SETPSOINUCIP" PARAMETERS="LPT16" POSSIBLEACTIONS="FALLOUTON_FAILUREREGION_SETPSOFAILED_FALSE" MAINTAINSESSION="NO" RESPONSE="-4" NEXTLEVEL="" /> 
       <METHOD NAME="SENDMESSAGE" PARAMETERS="" POSSIBLEACTIONS="FALLOUTONSUCCESS" MAINTAINSESSION="NO" RESPONSE="0" NEXTLEVEL="" /> 
      </INPUT> 
      <INPUT VALUE="LP60ACTIVATION"> 
       <METHOD NAME="SETPSOINUCIP" PARAMETERS="LP60" POSSIBLEACTIONS="FALLOUTON_FAILUREREGION_SETPSOFAILED_FALSE" MAINTAINSESSION="NO" RESPONSE="-4" NEXTLEVEL="" /> 
       <METHOD NAME="SENDMESSAGE" PARAMETERS="" POSSIBLEACTIONS="FALLOUTONSUCCESS" MAINTAINSESSION="NO" RESPONSE="0" NEXTLEVEL="" /> 
      </INPUT> 
      <INPUT VALUE="LPC16DEACTIVATION"> 
       <METHOD NAME="UNSETPSOINUCIP" PARAMETERS="LPC16" POSSIBLEACTIONS="FALLOUTON_FAILUREREGION_SETPSOFAILED_FALSE" MAINTAINSESSION="NO" RESPONSE="-4" NEXTLEVEL="" /> 
       <METHOD NAME="SENDMESSAGE" PARAMETERS="" POSSIBLEACTIONS="FALLOUTONSUCCESS" MAINTAINSESSION="NO" RESPONSE="0" NEXTLEVEL="" /> 
      </INPUT> 
      <INPUT VALUE="LP26DEACTIVATION"> 
       <METHOD NAME="UNSETPSOINUCIP" PARAMETERS="LP26" POSSIBLEACTIONS="FALLOUTON_FAILUREREGION_SETPSOFAILED_FALSE" MAINTAINSESSION="NO" RESPONSE="-4" NEXTLEVEL="" /> 
       <!--<METHOD NAME="SENDMESSAGE" PARAMETERS="" POSSIBLEACTIONS="FALLOUTONSUCCESS" MAINTAINSESSION="NO" RESPONSE="0" NEXTLEVEL="" />--> 
      </INPUT> 
      <INPUT VALUE="LP49DEACTIVATION"> 
       <METHOD NAME="UNSETPSOINUCIP" PARAMETERS="LP49" POSSIBLEACTIONS="FALLOUTON_FAILUREREGION_SETPSOFAILED_FALSE" MAINTAINSESSION="NO" RESPONSE="-4" NEXTLEVEL="" /> 
       <METHOD NAME="SENDMESSAGE" PARAMETERS="" POSSIBLEACTIONS="FALLOUTONSUCCESS" MAINTAINSESSION="NO" RESPONSE="0" NEXTLEVEL="" /> 
      </INPUT> 
      <INPUT VALUE="LPT16DEACTIVATION"> 
       <METHOD NAME="UNSETPSOINUCIP" PARAMETERS="LPT16" POSSIBLEACTIONS="FALLOUTON_FAILUREREGION_SETPSOFAILED_FALSE" MAINTAINSESSION="NO" RESPONSE="-4" NEXTLEVEL="" /> 
       <METHOD NAME="SENDMESSAGE" PARAMETERS="" POSSIBLEACTIONS="FALLOUTONSUCCESS" MAINTAINSESSION="NO" RESPONSE="0" NEXTLEVEL="" /> 
      </INPUT> 
      <INPUT VALUE="LP60DEACTIVATION"> 
       <METHOD NAME="UNSETPSOINUCIP" PARAMETERS="LP60" POSSIBLEACTIONS="FALLOUTON_FAILUREREGION_SETPSOFAILED_FALSE" MAINTAINSESSION="NO" RESPONSE="-4" NEXTLEVEL="" /> 
       <METHOD NAME="SENDMESSAGE" PARAMETERS="" POSSIBLEACTIONS="FALLOUTONSUCCESS" MAINTAINSESSION="NO" RESPONSE="0" NEXTLEVEL="" /> 
      </INPUT> 
      </INIT> 
      <FAILUREREGION INVALIDINPUTRESPONSE="-2"> 
      <INPUT VALUE="LOWBALANCE"> 
       <METHOD NAME="SENDMESSAGE" PARAMETERS="" POSSIBLEACTIONS="FALLOUTONSUCCESS" MAINTAINSESSION="NO" RESPONSE="1" NEXTLEVEL="" /> 
      </INPUT> 
      <INPUT VALUE="SETPSOFAILED"> 
       <METHOD NAME="SENDMESSAGE" PARAMETERS="" POSSIBLEACTIONS="FALLOUTONSUCCESS" MAINTAINSESSION="NO" RESPONSE="2" NEXTLEVEL="" /> 
      </INPUT> 
      <INPUT VALUE="UCIPDEBIT"> 
       <METHOD NAME="UNSETPSOINMINSAT" PARAMETERS="SLN7" POSSIBLEACTIONS="FALLOUTON_FAILUREREGION_UNSETPSO_FALSE" MAINTAINSESSION="NO" RESPONSE="-6" NEXTLEVEL="" /> 
       <METHOD NAME="SENDMESSAGE" PARAMETERS="" POSSIBLEACTIONS="FALLOUTONSUCCESS" MAINTAINSESSION="NO" RESPONSE="3" NEXTLEVEL="" /> 
      </INPUT> 
      <INPUT VALUE="UNSETPSO"> 
       <METHOD NAME="SENDMESSAGE" PARAMETERS="" POSSIBLEACTIONS="FALLOUTONSUCCESS" MAINTAINSESSION="NO" RESPONSE="4" NEXTLEVEL="" /> 
      </INPUT> 
      </FAILUREREGION> 
     </STATEINFORMATION> 
     <STATEINFORMATION TYPE="POSTPAID"> 
      <INIT INVALIDINPUTRESPONSE="-2"> 
      <INPUT VALUE=""> 
       <METHOD NAME="SENDMESSAGE" PARAMETERS="" POSSIBLEACTIONS="FALLOUTONSUCCESS" MAINTAINSESSION="NO" RESPONSE="5" NEXTLEVEL="" /> 
      </INPUT> 
      </INIT> 
     </STATEINFORMATION> 
     </NI> 
    </MODES> 
    </TN> 
    <KER> 
    <MODES> 
     <NI> 
     <STATEINFORMATION TYPE="PREPAID"> 
      <INIT INVALIDINPUTRESPONSE="-2"> 
      <INPUT VALUE="LP6ACTIVATION"> 
       <METHOD NAME="SETPSOINUCIP" PARAMETERS="LP6" POSSIBLEACTIONS="FALLOUTON_FAILUREREGION_SETPSOFAILED_FALSE" MAINTAINSESSION="NO" RESPONSE="-4" NEXTLEVEL="" /> 
       <METHOD NAME="SENDMESSAGE" PARAMETERS="" POSSIBLEACTIONS="FALLOUTONSUCCESS" MAINTAINSESSION="NO" RESPONSE="0" NEXTLEVEL="" /> 
      </INPUT> 
      <INPUT VALUE="LPSP15ACTIVATION"> 
       <METHOD NAME="SETPSOINUCIP" PARAMETERS="LPSP15" POSSIBLEACTIONS="FALLOUTON_FAILUREREGION_SETPSOFAILED_FALSE" MAINTAINSESSION="NO" RESPONSE="-4" NEXTLEVEL="" /> 
       <METHOD NAME="SENDMESSAGE" PARAMETERS="" POSSIBLEACTIONS="FALLOUTONSUCCESS" MAINTAINSESSION="NO" RESPONSE="0" NEXTLEVEL="" /> 
      </INPUT> 
      <INPUT VALUE="LP6DEACTIVATION"> 
       <METHOD NAME="UNSETPSOINUCIP" PARAMETERS="LP6" POSSIBLEACTIONS="FALLOUTON_FAILUREREGION_SETPSOFAILED_FALSE" MAINTAINSESSION="NO" RESPONSE="-4" NEXTLEVEL="" /> 
       <METHOD NAME="SENDMESSAGE" PARAMETERS="" POSSIBLEACTIONS="FALLOUTONSUCCESS" MAINTAINSESSION="NO" RESPONSE="0" NEXTLEVEL="" /> 
      </INPUT> 
      <INPUT VALUE="LPSP15DEACTIVATION"> 
       <METHOD NAME="UNSETPSOINUCIP" PARAMETERS="LPSP15" POSSIBLEACTIONS="FALLOUTON_FAILUREREGION_SETPSOFAILED_FALSE" MAINTAINSESSION="NO" RESPONSE="-4" NEXTLEVEL="" /> 
       <METHOD NAME="SENDMESSAGE" PARAMETERS="" POSSIBLEACTIONS="FALLOUTONSUCCESS" MAINTAINSESSION="NO" RESPONSE="0" NEXTLEVEL="" /> 
      </INPUT> 
      <INPUT VALUE="LP6SUBSCRIPTION"> 
       <METHOD NAME="CHECKSUBSCRIBERBALANCE" PARAMETERS="LP6" POSSIBLEACTIONS="FALLOUTON_FAILUREREGION_LOWBALANCE_INSUFFICIENTBALANCE" MAINTAINSESSION="NO" RESPONSE="-3" NEXTLEVEL="" /> 
       <METHOD NAME="SETPSOINUCIP" PARAMETERS="LP6" POSSIBLEACTIONS="FALLOUTON_FAILUREREGION_SETPSOFAILED_FALSE" MAINTAINSESSION="NO" RESPONSE="-4" NEXTLEVEL="" /> 
       <METHOD NAME="FIREUCIPDEBIT" PARAMETERS="LP6" POSSIBLEACTIONS="FALLOUTON_FAILUREREGION_CHARGINGFAILED_FALSE" MAINTAINSESSION="NO" RESPONSE="-4" NEXTLEVEL="" /> 
       <METHOD NAME="SENDMESSAGE" PARAMETERS="" POSSIBLEACTIONS="FALLOUTONSUCCESS" MAINTAINSESSION="NO" RESPONSE="0" NEXTLEVEL="" /> 
      </INPUT> 
      </INIT> 
      <FAILUREREGION INVALIDINPUTRESPONSE="-2"> 
      <INPUT VALUE="LOWBALANCE"> 
       <METHOD NAME="SENDMESSAGE" PARAMETERS="" POSSIBLEACTIONS="FALLOUTONSUCCESS" MAINTAINSESSION="NO" RESPONSE="1" NEXTLEVEL="" /> 
      </INPUT> 
      <INPUT VALUE="CHARGINGFAILED"> 
       <METHOD NAME="UNSETPSOINUCIP" PARAMETERS="LP6" POSSIBLEACTIONS="FALLOUTON_FAILUREREGION_SETPSOFAILED_FALSE" MAINTAINSESSION="NO" RESPONSE="-4" NEXTLEVEL="" /> 
       <METHOD NAME="SENDMESSAGE" PARAMETERS="" POSSIBLEACTIONS="FALLOUTONSUCCESS" MAINTAINSESSION="NO" RESPONSE="6" NEXTLEVEL="" /> 
      </INPUT> 
      <INPUT VALUE="SETPSOFAILED"> 
       <METHOD NAME="SENDMESSAGE" PARAMETERS="" POSSIBLEACTIONS="FALLOUTONSUCCESS" MAINTAINSESSION="NO" RESPONSE="2" NEXTLEVEL="" /> 
      </INPUT> 
      <INPUT VALUE="UCIPDEBIT"> 
       <METHOD NAME="UNSETPSOINMINSAT" PARAMETERS="SLN7" POSSIBLEACTIONS="FALLOUTON_FAILUREREGION_UNSETPSO_FALSE" MAINTAINSESSION="NO" RESPONSE="-6" NEXTLEVEL="" /> 
       <METHOD NAME="SENDMESSAGE" PARAMETERS="" POSSIBLEACTIONS="FALLOUTONSUCCESS" MAINTAINSESSION="NO" RESPONSE="3" NEXTLEVEL="" /> 
      </INPUT> 
      <INPUT VALUE="UNSETPSO"> 
       <METHOD NAME="SENDMESSAGE" PARAMETERS="" POSSIBLEACTIONS="FALLOUTONSUCCESS" MAINTAINSESSION="NO" RESPONSE="4" NEXTLEVEL="" /> 
      </INPUT> 
      </FAILUREREGION> 
     </STATEINFORMATION> 
     <STATEINFORMATION TYPE="POSTPAID"> 
      <INIT INVALIDINPUTRESPONSE="-2"> 
      <INPUT VALUE=""> 
       <METHOD NAME="SENDMESSAGE" PARAMETERS="" POSSIBLEACTIONS="FALLOUTONSUCCESS" MAINTAINSESSION="NO" RESPONSE="5" NEXTLEVEL="" /> 
      </INPUT> 
      </INIT> 
     </STATEINFORMATION> 
     </NI> 
    </MODES> 
    </KER> 
</SESSIONANALYSER>

來源

2012-05-18 Charu

什麼是拋出「沒有設置對象實例的對象引用」錯誤？一個C＃程序？ – mzjn

是的，問題解決了。當xpath無法找到路徑時，我總是得到這個異常！ – Charu

XPath表達式您正在評估：

//SESSIONANALYSER/KER/MODES/NI/STATEINFORMATION[@TYPE='PREPAID']/INIT/INPUT

選擇不只有一個，但六個INPUT元素。

您指定要在之後的第一個之後添加新元素。

因此，使用該XPath表達式，它選擇只有一個（在對需要的）INPUT元件：

(//SESSIONANALYSER/KER/MODES/NI/STATEINFORMATION[@TYPE='PREPAID']/INIT/INPUT)[1]

大多數的XPath引擎提供一個SelectNodes()方法，返回在NodeList和所選擇的節點的程序員需要遍歷這個集合 - 即使只選擇了一個節點 - 記住這一點。

來源

2012-05-18 12:09:03

我不確定爲什麼你的xpath中有BH。

此XPath查詢從您的樣品只選擇一個元素，我認爲這是你想要的：

/SESSIONANALYSER/KER/MODES/NI/STATEINFORMATION[@TYPE='PREPAID'] 
    /INIT[@INVALIDINPUTRESPONSE='-2'] 
    /INPUT[@VALUE='LP6ACTIVATION']

來源

2012-05-18 09:20:40 MattH

對不起，我編輯了xpath，它只是KER，而不是BH – Charu

我建議你使用xpath嗎？ – MattH

我必須給這些值@ VALUE ='LP6ACTIVATION'嗎？我的意思是隻有一個INPUT標籤，實際上我沒有這個值在當前的情況下。 – Charu

當使用xpath爲xml添加元素時，對象引用未設置爲對象的實例

回答

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