MQL4参考图表操作 ChartGetDouble

ChartGetDouble

Returns the value of a corresponding property of the specified chart. Chart property must be of double type. There are 2 variants of the function calls.

1. Returns the property value directly.

double  ChartGetDouble(
   long  chart_id,          // Chart ID
   int   prop_id,           // Property ID
   int   sub_window=0       // subwindow number, if necessary
   );

2. Returns true or false, depending on the success of a function. If successful, the value of the property is placed in a target variable double_var passed by reference.

bool  ChartGetDouble(
   long    chart_id,        // Chart ID
   int     prop_id,         // Property ID
   int     sub_window,      // Subwindow number
   double& double_var       // Target variable for the chart property
   );

Parameters

chart_id

[in] Chart ID. 0 means the current chart.

prop_id

[in] Chart property ID. This value can be one of the ENUM_CHART_PROPERTY_DOUBLE values.

sub_window

[in] Number of the chart subwindow. For the first case, the default value is 0 (main chart window). The most of the properties do not require a subwindow number.

double_var

[out] Target variable of double type for the requested property.

Return Value

The value of double type.

For the second call case it returns true if the specified property is available and its value has been placed into double_var variable, otherwise returns false. To get an additional information about the error, it is necessary to call the function GetLastError().

Example:

void OnStart()
  {
   double priceMin=ChartGetDouble(0,CHART_PRICE_MIN,0);
   double priceMax=ChartGetDouble(0,CHART_PRICE_MAX,0);
   Print("CHART_PRICE_MIN =",priceMin);
   Print("CHART_PRICE_MAX =",priceMax);
  }

ChartSetStringChartGetInteger