blocks|key|489318|text|它就像这样简单：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|489319|String+xmlfile+=+Data_Array["XML_File"];|code-block|syntax|javascript|489320|请注意，如果字典没有等于"XML_File"的键，则该代码将抛出异常。如果你想先检查，你可以像这样使用TryGetValue：|offset|length|style|CODE|489321|string+xmlfile;
if+(!Data_Array.TryGetValue("XML_File",+out+xmlfile))+{
+++//+the+key+isn't+in+the+dictionary.
+++return;+//+or+whatever+you+want+to+do
}
//+xmlfile+is+now+equal+to+the+value|489322|entityMap^0|0|0|C|A|0|0^^$0|@$1|2|3|4|5|6|7|Q|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|R|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|S|8|@$I|T|J|U|K|L]]|9|@]|A|$]]|$1|M|3|N|5|D|7|V|8|@]|9|@]|A|$E|F]]|$1|O|3|-4|5|6|7|W|8|@]|9|@]|A|$]]]|P|$]]

It's as simple as this:

<pre><code>String xmlfile = Data_Array["XML_File"];
</code></pre>

Note that if the dictionary doesn't have a key that equals <code>"XML_File"</code>, that code will throw an exception. If you want to check first, you can use TryGetValue like this:

<pre><code>string xmlfile;
if (!Data_Array.TryGetValue("XML_File", out xmlfile)) {
 // the key isn't in the dictionary.
 return; // or whatever you want to do
}
// xmlfile is now equal to the value
</code></pre>

blocks|key|489519|text|只需使用字典上的密钥名称。C#具有以下特性：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|489520|+Dictionary<string,+string>+dict+=+new+Dictionary<string,+string>();
+dict.Add("UserID",+"test");
+string+userIDFromDictionaryByKey+=+dict["UserID"];|code-block|syntax|javascript|489521|如果你看一下提示建议：|489522|​|489523|📷|atomic|offset|length|489524|489525|entityMap|0|IMAGE|mutability|IMMUTABLE|imageUrl|https://ask.qcloudimg.com/http-save/yehe-900000/2e30f99c859072af7e061dcc1f3a035c.png|imageAlt^0|0|0|0|0|0|1|0|0|0^^$0|@$1|2|3|4|5|6|7|Z|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|10|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|11|8|@]|9|@]|A|$]]|$1|I|3|J|5|6|7|12|8|@]|9|@]|A|$]]|$1|K|3|L|5|M|7|13|8|@]|9|@$N|14|O|15|1|16]]|A|$]]|$1|P|3|J|5|6|7|17|8|@]|9|@]|A|$]]|$1|Q|3|-4|5|6|7|18|8|@]|9|@]|A|$]]]|R|$S|$5|T|U|V|A|$W|X|Y|-4]]]]

Just use the key name on the dictionary. C# has this:
<pre><code> Dictionary&lt;string, string&gt; dict = new Dictionary&lt;string, string&gt;();
 dict.Add(&quot;UserID&quot;, &quot;test&quot;);
 string userIDFromDictionaryByKey = dict[&quot;UserID&quot;];
</code></pre>
If you look at the tip suggestion:
<a href="https://i.stack.imgur.com/pPx9E.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/pPx9E.png" alt="Enter image description here" /></a>

blocks|key|272288|text|这不是TryGetValue的工作方式。它根据是否找到键返回true或false，如果键在那里，则将其out参数设置为相应值。|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|272289|如果您想检查密钥是否在那里，并在它丢失时执行某些操作，则需要如下所示：|272290|bool+hasValue+=+Data_Array.TryGetValue("XML_File",+out+value);
if+(hasValue)+{
++++xmlfile+=+value;
}+else+{
++++//+do+something+when+the+value+is+not+there
}|code-block|syntax|javascript|272291|entityMap^0|3|B|U|4|Z|5|1F|3|0|0|0^^$0|@$1|2|3|4|5|6|7|O|8|@$9|P|A|Q|B|C]|$9|R|A|S|B|C]|$9|T|A|U|B|C]|$9|V|A|W|B|C]]|D|@]|E|$]]|$1|F|3|G|5|6|7|X|8|@]|D|@]|E|$]]|$1|H|3|I|5|J|7|Y|8|@]|D|@]|E|$K|L]]|$1|M|3|-4|5|6|7|Z|8|@]|D|@]|E|$]]]|N|$]]

That is not how the <code>TryGetValue</code> works. It returns <code>true</code> or <code>false</code> based on whether the key is found or not, and sets its <code>out</code> parameter to the corresponding value if the key is there.

If you want to check if the key is there or not and do something when it's missing, you need something like this:

<pre><code>bool hasValue = Data_Array.TryGetValue("XML_File", out value);
if (hasValue) {
 xmlfile = value;
} else {
 // do something when the value is not there
}
</code></pre>

blocks|key|489532|text|Dictionary<String,+String>+d+=+new+Dictionary<String,+String>();
d.Add("1",+"Mahadev");
d.Add("2",+"Mahesh");
Console.WriteLine(d["1"]);+//+It+will+print+Value+of+key+'1'|type|code-block|depth|inlineStyleRanges|entityRanges|data|syntax|javascript|489533|unstyled|entityMap^0|0^^$0|@$1|2|3|4|5|6|7|G|8|@]|9|@]|A|$B|C]]|$1|D|3|-4|5|E|7|H|8|@]|9|@]|A|$]]]|F|$]]

<pre><code>Dictionary&lt;String, String&gt; d = new Dictionary&lt;String, String&gt;();
d.Add(&quot;1&quot;, &quot;Mahadev&quot;);
d.Add(&quot;2&quot;, &quot;Mahesh&quot;);
Console.WriteLine(d[&quot;1&quot;]); // It will print Value of key '1'
</code></pre>

blocks|key|489377|text|static+void+XML_Array(Dictionary<string,+string>+Data_Array)
{
++++String+value;
++++if(Data_Array.TryGetValue("XML_File",+out+value))
++++{
++++++++//+...+Do+something+here+with+value+...
++++}
}|type|code-block|depth|inlineStyleRanges|entityRanges|data|syntax|javascript|489378|unstyled|entityMap^0|0^^$0|@$1|2|3|4|5|6|7|G|8|@]|9|@]|A|$B|C]]|$1|D|3|-4|5|E|7|H|8|@]|9|@]|A|$]]]|F|$]]

<pre><code>static void XML_Array(Dictionary&lt;string, string&gt; Data_Array)
{
 String value;
 if(Data_Array.TryGetValue(&quot;XML_File&quot;, out value))
 {
 // ... Do something here with value ...
 }
}
</code></pre>

blocks|key|489391|text|static+String+findFirstKeyByValue(Dictionary<string,+string>+Data_Array,+String+value)
{
++++if+(Data_Array.ContainsValue(value))
++++{
++++++++foreach+(String+key+in+Data_Array.Keys)
++++++++{
++++++++++++if+(Data_Array[key].Equals(value))
++++++++++++++++return+key;
++++++++}
++++}
++++return+null;
}|type|code-block|depth|inlineStyleRanges|entityRanges|data|syntax|javascript|489392|unstyled|entityMap^0|0^^$0|@$1|2|3|4|5|6|7|G|8|@]|9|@]|A|$B|C]]|$1|D|3|-4|5|E|7|H|8|@]|9|@]|A|$]]]|F|$]]

<pre><code>static String findFirstKeyByValue(Dictionary&lt;string, string&gt; Data_Array, String value)
{
 if (Data_Array.ContainsValue(value))
 {
 foreach (String key in Data_Array.Keys)
 {
 if (Data_Array[key].Equals(value))
 return key;
 }
 }
 return null;
}
</code></pre>

blocks|key|272318|text|private+void+button2_Click(object+sender,+EventArgs+e)
{
++++Dictionary<string,+string>+Data_Array+=+new+Dictionary<string,+string>();
++++Data_Array.Add("XML_File",+"Settings.xml");

++++XML_Array(Data_Array);
}

static+void+XML_Array(Dictionary<string,+string>+Data_Array)
{
++++String+xmlfile+=+Data_Array["XML_File"];
}|type|code-block|depth|inlineStyleRanges|entityRanges|data|syntax|javascript|272319|unstyled|entityMap^0|0^^$0|@$1|2|3|4|5|6|7|G|8|@]|9|@]|A|$B|C]]|$1|D|3|-4|5|E|7|H|8|@]|9|@]|A|$]]]|F|$]]

<pre><code>private void button2_Click(object sender, EventArgs e)
{
 Dictionary&lt;string, string&gt; Data_Array = new Dictionary&lt;string, string&gt;();
 Data_Array.Add(&quot;XML_File&quot;, &quot;Settings.xml&quot;);

 XML_Array(Data_Array);
}

static void XML_Array(Dictionary&lt;string, string&gt; Data_Array)
{
 String xmlfile = Data_Array[&quot;XML_File&quot;];
}
</code></pre>

blocks|key|489464|text|我在函数中使用与dasblinkenlight类似的方法，从包含加载到Dictionary中的JSON数组的Cookie返回单个键值，如下所示：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|489465|++++///+<summary>
++++///+Gets+a+single+key+Value+from+a+Json+filled+cookie+with+'cookiename','key'+
++++///+</summary>
++++public+static+string+GetSpecialCookieKeyVal(string+_CookieName,+string+_key)
++++{
++++++++//CALL+COOKIE+VALUES+INTO+DICTIONARY
++++++++Dictionary<string,+string>+dictCookie+=
++++++++JsonConvert.DeserializeObject<Dictionary<string,+string>>
+++++++++(MyCookinator.Get(_CookieName));

++++++++string+value;
++++++++if+(dictCookie.TryGetValue(+_key,+out+value))
++++++++{
++++++++++++return+value;
++++++++}
++++++++else
++++++++{
++++++++++++return+"0";
++++++++}

++++}|code-block|syntax|javascript|489466|其中"MyCookinator.Get()“是另一个简单的Cookie函数，它获取http+cookie的整体值。|489467|entityMap^0|0|0|0^^$0|@$1|2|3|4|5|6|7|K|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|L|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|M|8|@]|9|@]|A|$]]|$1|I|3|-4|5|6|7|N|8|@]|9|@]|A|$]]]|J|$]]

I use a similar method to dasblinkenlight's in a function to return a single key value from a Cookie containing a JSON array loaded into a Dictionary as follows:

<pre><code> /// &lt;summary&gt;
 /// Gets a single key Value from a Json filled cookie with 'cookiename','key' 
 /// &lt;/summary&gt;
 public static string GetSpecialCookieKeyVal(string _CookieName, string _key)
 {
 //CALL COOKIE VALUES INTO DICTIONARY
 Dictionary&lt;string, string&gt; dictCookie =
 JsonConvert.DeserializeObject&lt;Dictionary&lt;string, string&gt;&gt;
 (MyCookinator.Get(_CookieName));

 string value;
 if (dictCookie.TryGetValue( _key, out value))
 {
 return value;
 }
 else
 {
 return "0";
 }

 }
</code></pre>

Where "MyCookinator.Get()" is another simple Cookie function getting an http cookie overall value.

blocks|key|272469|text|Dictionary<int,string>+dict+=+new+Dictionary<int,string>{
++{1,"item1"},
++{2,"item2"},
++{3,"item3"},
}

int+key+=+2+//+for+example
string+result+=+dict.ContainsKey(key)+?+dict[key]+:+null;|type|code-block|depth|inlineStyleRanges|entityRanges|data|syntax|javascript|272470|unstyled|entityMap^0|0^^$0|@$1|2|3|4|5|6|7|G|8|@]|9|@]|A|$B|C]]|$1|D|3|-4|5|E|7|H|8|@]|9|@]|A|$]]]|F|$]]

<pre><code>Dictionary&lt;int,string&gt; dict = new Dictionary&lt;int,string&gt;{
 {1,&quot;item1&quot;},
 {2,&quot;item2&quot;},
 {3,&quot;item3&quot;},
}

int key = 2 // for example
string result = dict.ContainsKey(key) ? dict[key] : null;
</code></pre>

blocks|key|489562|text|if+(Data_Array["XML_File"]+!=+"")+String+xmlfile+=+Data_Array["XML_File"];|type|code-block|depth|inlineStyleRanges|entityRanges|data|syntax|javascript|489563|unstyled|entityMap^0|0^^$0|@$1|2|3|4|5|6|7|G|8|@]|9|@]|A|$B|C]]|$1|D|3|-4|5|E|7|H|8|@]|9|@]|A|$]]]|F|$]]

<pre><code>if (Data_Array["XML_File"] != "") String xmlfile = Data_Array["XML_File"];
</code></pre>

How can I get the dictionary value by a key on a function?
My function code (and the command I try doesn't work):
<pre><code>static void XML_Array(Dictionary&lt;string, string&gt; Data_Array)
{
 String xmlfile = Data_Array.TryGetValue(&quot;XML_File&quot;, out value);
}
</code></pre>
My button code:
<pre><code>private void button2_Click(object sender, EventArgs e)
{
 Dictionary&lt;string, string&gt; Data_Array = new Dictionary&lt;string, string&gt;();
 Data_Array.Add(&quot;XML_File&quot;, &quot;Settings.xml&quot;);

 XML_Array(Data_Array);
}
</code></pre>
I want on the <code>XML_Array</code> function the variable to be:
<pre><code>string xmlfile = &quot;Settings.xml&quot;:
</code></pre>

Get dictionary value by key

如何通过函数上的键获取字典的值？我的函数代码(以及我尝试的命令不起作用)：static void XML_Array(Dictionary<string, string> Data_Array){ String xmlfile = Data_Array.TryGetValue("XML_File", out value);}我的按钮代码：private void button2_Click(

问按键获取字典值
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