85 lines
2.3 KiB
Markdown
85 lines
2.3 KiB
Markdown
# GetDouble
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Provides simplified access to the functions of API MQL5 [ObjectGetDouble()](/en/docs/objects/objectgetdouble) to receive double values (of float and double types) of a graphical object bound to a class instance. There are two versions of the function call:
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Getting a property value without checking the correctness
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```
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double GetDouble(
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ENUM_OBJECT_PROPERTY_DOUBLE prop_id, // integer property ID
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int modifier=-1 // modifier
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) const
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```
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Parameters
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prop_id
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[in] ID of the graphical object double property.
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modifier=-1
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[in] Modifier (index) of a double property.
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Return Value
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Value of a double property - success, [EMPTY_VALUE](/en/docs/constants/namedconstants/otherconstants) - cannot receive a double property.
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Getting a property value in verifying the correctness of such treatment
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```
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bool GetDouble(
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ENUM_OBJECT_PROPERTY_DOUBLE prop_id, // double property ID
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int modifier, // modifier
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double& value // link to a variable
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) const
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```
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Parameters
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prop_id
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[in] ID of a graphical object double property.
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modifier
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[in] Modifier (index) of a double property.
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value
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[out] Link to a variable to place a double property value.
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Return Value
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true - success, false - cannot get a double property.
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Example:
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```
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//--- example for CChartObject::GetDouble
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#include <ChartObjects\ChartObject.mqh>
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//---
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void OnStart()
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{
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CChartObject object;
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//---
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for(int i=0;i<object.LevelsCount();i++)
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{
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//--- get levels value by easy method
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printf("Level %d value=%f",i,object.GetDouble(OBJPROP_LEVELVALUE,i));
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//--- get levels value by classic method
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double value;
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if(!object.SetDouble(OBJPROP_LEVELVALUE,i,value))
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{
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printf("Get double property error %d",GetLastError());
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return;
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}
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else
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printf("Level %d value=%f",i,value);
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}
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}
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```
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