SemanticValue.ContainsKey Method (String)

 

Indicates whether the current SemanticValue instance collection contains a child SemanticValue instance with a given key string.

Namespace:   System.Speech.Recognition
Assembly:  System.Speech (in System.Speech.dll)

public bool ContainsKey(
	string key
)

Parameters

key
Type: System.String

String containing the key string used to identify a child instance of SemanticValue under the current SemanticValue.

Return Value

Type: System.Boolean

Returns a bool, true if a child instance SemanticValue tagged with the string key is found, false if not.

You can only access data by key value at runtime, for example to check semantic["myKey"].Value, and this generates an exception. We recommend that you query the object with ContainsKey before using Item with a given instance of SemanticValue.

The following example shows a handler for a SpeechRecognized event designed to handle commands to change foreground and background color.

After handling phrases that are recognized but have no semantic structure, the handler checks for the presence of appropriate keys using ContainsKey (applyChgToBackground, colorRGBValueList, or colorStringList), and then processes the semantically organized data.


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 semantics 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 Foreground.
      if (ForeColor.GetBrightness() <= .50) 
      {
        BackColor = Color.White;
      }
      else 
      {
        BackColor = Color.Black;
      }
    }
    return;
  };

.NET Framework
Available since 3.0
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