关于Aggregate字段合计(100分)

L

louchanghong

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• 2003-05-13

• #1

dbgrid1-->datasource1-->clientdataset1-->DataSetProvider1-->query1
query1.sql:='select * from table1';
对query1,clientdataset1,dbgrid1 分别建 立 了永久字段，和永久列对象，在
clientdataset1中建了一个Aggregate合计字段叫 fld1
在btn1的单击事件中label1.caption:=fld1.value;或edit1.text:=fld1.value;
都提示错误。Invalid variant type conversion。
fld1.expression:=sum(shl)//是数量为12
为什么

 

A

antic_ant

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• 2003-05-13

• #2

你要给Aggregate字段一个类型

 

L

lvxq

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• 2003-05-13

• #3

edit1.text:=datasource1.Dataset.FieldByName('aggregate').asString;

 

L

louchanghong

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• 2003-05-14

• #4

当fld1的值为15时
用vartoatr(clientdatasetfld1.value) 只能返回' '即value的值为null
但在表中被合计的这个字段的值为15。
query1.设为缓存更新

 

S

shiningplus

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• 2003-05-14

• #5

ClientDataSet1.AggregatesActive:=True;
clientdatasetfld1.actvie:=True

 

郭

郭玉梁

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• 2003-05-14

• #6

to antic_ant:
Aggregate's field type is readonly!

 

L

louchanghong

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• 2003-05-15

• #7

接受答案了.