SemanticValue.Item[String] 屬性

定義

命名空間:

System.Speech.Recognition

組件:

System.Speech.dll

套件:

System.Speech v11.0.0-preview.7.26381.103

來源:

SemanticValue.cs

回傳屬於目前 SemanticValue的子SemanticValue實例。

public:
 property System::Speech::Recognition::SemanticValue ^ default[System::String ^] { System::Speech::Recognition::SemanticValue ^ get(System::String ^ key); void set(System::String ^ key, System::Speech::Recognition::SemanticValue ^ value); };

public System.Speech.Recognition.SemanticValue this[string key] { get; set; }

member this.Item(string) : System.Speech.Recognition.SemanticValue with get, set

Default Public Property Item(key As String) As SemanticValue

參數

key

String

一個包含於當前實例KeyValuePair<String, SemanticValue>中的 的SemanticValue鍵。

屬性值

SemanticValue

回傳一個可作為鍵值對索引的當前 SemanticValue 子節點： KeyValuePair<String,SemanticValue>。

實作

Item[TKey]

例外狀況

KeyNotFoundException

目前實例中 SemanticValue 沒有任何子成員擁有與參數相符 key 的金鑰。

InvalidOperationException

程式碼嘗試在指定的索引處更改 。SemanticValue

範例

以下範例展示了一個處理事件處理程序的處理器 SpeechRecognized ，該事件旨在處理改變前景與背景顏色的指令。

處理無語意結構的識別片語後，處理器會用 ContainsKey （applyChgToBackground， colorRGBValueList， 或 colorStringList)） 檢查是否存在適當的鍵，然後利用該 Item[] 屬性取得所需資訊的節點。

以下重點說明了 的 Item[] 使用情況。

newGrammar.SpeechRecognized +=
  delegate(object sender, SpeechRecognizedEventArgs eventArgs)
  {

    // Retrieve the value of the semantic property.
    bool changeBackGround = true;
    string errorString = "";
    SemanticValue semantics = eventArgs.Result.Semantics;

    Color newColor = Color.Empty;

    try
    {
      if (semantics.Count == 0 && semantics.Value==null)
      {
        // Signifies recognition by a grammar with no semantics.
        // Parse the string, assuming that the last word is color,
        //  searching for background or foreground in input.
        if (eventArgs.Result.Text.Contains("foreground"))
        {
          changeBackGround = false;
        }
        string cName = eventArgs.Result.Words[eventArgs.Result.Words.Count - 1].Text;
        newColor = Color.FromName(cName);

      }
      else if (semantics.ContainsKey("colorStringList") ^ semantics.ContainsKey("colorRGBValueList"))
      {

        // Determine whether to change background or foreground.
        if (semantics.ContainsKey("applyChgToBackground"))
        {
          changeBackGround = semantics["applyChgToBackground"].Value is bool;
        }

        // Get the RGB color value.
        if (semantics.ContainsKey("colorStringList"))
        {
          newColor = Color.FromName((string)semantics["colorStringList"].Value);
        }
        if (semantics.ContainsKey("colorRGBValueList"))
        {
          newColor = System.Drawing.Color.FromArgb((int)semantics["colorRGBValueList"].Value);
        }
      }
      else
      {

        // Throw an exception if the semantics do not contain the keys we
        // support.
        throw(new Exception("Unsupported semantic keys found."));
      }
    }

    catch (Exception exp)
    {
      MessageBox.Show(String.Format("Unable to process color semantics.:\n{0}\n", exp.Message));
      return;
    }

    // Change colors, either foreground or background.
    if (changeBackGround)
    {
      BackColor = newColor;
      float Bright = BackColor.GetBrightness();
      float Hue = BackColor.GetHue();
      float Sat = BackColor.GetSaturation();
      // Make sure that text is readable regardless of background.
      if (BackColor.GetBrightness() <= .50)
      {
        ForeColor = Color.White;
      }
      else
      {
        ForeColor = Color.Black;
      }
    }
    else
    {
      ForeColor = newColor;
      float Bright = ForeColor.GetBrightness();
      float Hue = ForeColor.GetHue();
      float Sat = ForeColor.GetSaturation();

      // Make sure that text is readable regardless of the foreground.
      if (ForeColor.GetBrightness() <= .50)
      {
        BackColor = Color.White;
      }
      else
      {
        BackColor = Color.Black;
      }
    }
    return;
  };

備註

該 為 Item[] 唯讀，若成員被修改則產生例外。

你只能在執行時依照鍵值存取資料，無法在編譯時存取資料，例如檢查 semantic["myKey"].Value。 指定不存在的鍵會產生例外。

要偵測某個金鑰的存在，請在實ContainsKey例上使用該SemanticValue屬性。