FastReport 变量列表使用

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转载最新推荐文章于 2026-04-12 11:06:42 发布 315 阅读 AI 写同款· GEO 优化 ›

使用报表变量时，引用“frxVariables”单元。变量定义在“TfrxVariable” 类：

TfrxVariable = class(TCollectionItem)

published

property Name: String; //Name of a variable

property Value: Variant; //Value of a variable

end;

变量列表在“TfrxVariables” 类，有所有相关的方法：

TfrxVariables = class(TCollection)

public

function Add: TfrxVariable; //Adds a variable to the end of the list

function Insert(Index: Integer): TfrxVariable; //Adds a variable to the given position of the list

function IndexOf(const Name: String): Integer; //Returns the index of a variable with the given name

procedure AddVariable(const ACategory, AName: String; const AValue: Variant); //Adds a variable to the specified category

procedure DeleteCategory(const Name: String); //Deletes a category and all its variables

procedure DeleteVariable(const Name: String); //Deletes a variable

procedure GetCategoriesList(List: TStrings; ClearList: Boolean = True); //Returns the list of categories

procedure GetVariablesList(const Category: String; List: TStrings); //Returns the list of variables in the specified category

property Items[Index: Integer]: TfrxVariable readonly; //The list of variables

property Variables[Index: String]: Variant; default; //Values of variables

end;

如果变量的列表很长，可以按类别分组。例如，当有下列变量列表:

Customer name

Account number

in total

total vat

可以使用以下方式：

Properties

Customer name

Account number

Totals

In total

total vat

有以下局限：

- 必须创建至少一个类别

- 类别在data tree下层, 变量在第二层

- 类别不能嵌套

- 变量的名称必须是唯一的，在整体列表中，而不是在一个类别中

一：创建一个变量列表

A link to the report variables is stored in the “TfrxReport.Variables” property. To create a list manually, the following steps must be performed:

- clear the list

- create a category

- create variables

- repeat the 2 and 3 steps to create another category

二：清空变量列表

It is performed with the help of the “TfrxVariables.Clear” method:

frxReport1.Variables.Clear;

三：添加分类

必需至少创建一个类别，类别和变量保存在一个list。类别不同于变量是以一个空格开始，这是名字的第一个符号.所有的变量都是属于这一类别。

有两个方法添加类别：

frxReport1.Variables[' ' + 'My Category 1'] := Null;

var

Category: TfrxVariable;

Category := frxReport1.Variables.Add;

Category.Name := ' ' + 'My category 1';

四：添加变量

添加变量必须在类别添加以后，在列表中变量名必须唯一, 并且必须在类别中。

这里有几个方法添加变量到列表:

frxReport1.Variables['My Variable 1'] := 10; // 添加(如果不存在) 或修改一个变量的值。

var

Variable: TfrxVariable;

Variable := frxReport1.Variables.Add;

Variable.Name := 'My Variable 1';

Variable.Value := 10;

以上2个方法都把变量添加到列表最后, 因此, 添加到最后的类别. 如果想添加到列表的指定位置,使用“Insert” 方法:

var

Variable: TfrxVariable;

Variable := frxReport1.Variables.Insert(1);

Variable.Name := 'My Variable 1';

Variable.Value := 10;

添加到指定的类别,使用“AddVariable” 方法:

frxReport1.Variables.AddVariable('My Category 1', 'My Variable 2', 10);

五：删除变量

frxReport1.Variables.DeleteVariable('My Variable 2');

六：删除分类

frxReport1.Variables.DeleteCategory('My Category 1');

七：修改变量值

八：脚本变量

你可以在TfrxReport.Script中定义脚本变量，用来代替report变量，看看 report变量和 script变量的不同:

	Report variables	Script variables
位置	In the report variables list, TfrxReport.Variables.	In the report script, TfrxReport.Script.Variables.
Variable name	May contain any symbols.	May contain any symbols. But if you want to use that variable inside the report script, its name should conform to Pascal identificator specifications.
Variable value	May be of any type. Variables of string type are calculated each time you access them, and are, in itself, an expressions.	May be of any type. No calculation is performed, behavior is like standard language variable.
可访问性	Programmer can see the list of report variables in the "Data tree" window.	The variable is not visible, programmer should know about it.

Working with script variables is easy. Just assign value to the variable this way:

frxReport1.Script.Variables['My Variable'] := 'test';

In this case FastReport will create a variable if it is not exists, or assign a value to it. There is no need to use extra quotes when assigning a string to that variable.