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03-UnrealEngine/Gameplay/UObject/UnrealSpecifiers/Meta/Numeric/Multiple/Multiple.md

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+# Multiple
+
+- **功能描述：** 指定数字的值必须是Mutliple提供的值的整数倍。
+- **使用位置：** UPROPERTY
+- **引擎模块：** Numeric Property
+- **元数据类型：** int32
+- **限制类型：** int32
+- **常用程度：** ★★★
+
+指定数字的值必须是Mutliple提供的值的整数倍。
+
+## 测试代码：
+
+```cpp
+public:
+	UPROPERTY(EditAnywhere, BlueprintReadWrite, Category = MultipleTest)
+	int32 MyInt_NoMultiple = 100;
+
+	UPROPERTY(EditAnywhere, BlueprintReadWrite, Category = MultipleTest, meta = (Multiple = 5))
+	int32 MyInt_HasMultiple = 100;
+```
+
+## 蓝图效果：
+
+可以看到，拥有Multiple 的只能按照5的倍数来增长。
+
+![Multiple](Multiple.gif)
+
+## 原理：
+
+```cpp
+template <typename Type>
+static Type ClampIntegerValueFromMetaData(Type InValue, FPropertyHandleBase& InPropertyHandle, FPropertyNode& InPropertyNode)
+{
+	Type RetVal = ClampValueFromMetaData<Type>(InValue, InPropertyHandle);
+
+	//if there is "Multiple" meta data, the selected number is a multiple
+	const FString& MultipleString = InPropertyHandle.GetMetaData(TEXT("Multiple"));
+	if (MultipleString.Len())
+	{
+		check(MultipleString.IsNumeric());
+		Type MultipleValue;
+		TTypeFromString<Type>::FromString(MultipleValue, *MultipleString);
+		if (MultipleValue != 0)
+		{
+			RetVal -= Type(RetVal) % MultipleValue;
+		}
+	}
+
+	return RetVal;
+}
+```