model/view call setdata() function help?

[jpn]

Don't use -1 to query an index. It will return an invalid index.

ModelData->insertRows(0, 1);
ModelData->setData( ModelData->index(0), &addMe, Qt::DisplayRole);

ModelData->insertRows(0, 1);
ModelData->setData( ModelData->index(0), &addMe, Qt::DisplayRole);

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Also, I'm afraid there is something wrong with the way the custom struct is passed around:

void CParamDialog::on_ButtonAdd_clicked()
{
   Model::XianStruct addMe;
   ...
   ModelData->setData(..., &addMe, ...);
}
 
bool Model::setData(const QModelIndex &index, const QVariant &value, int role )
{ 
   ...
   XianStruct newData = value.value<XianStruct>();
   ...
}

void CParamDialog::on_ButtonAdd_clicked()
{
   Model::XianStruct addMe;
   ...
   ModelData->setData(..., &addMe, ...);
}

bool Model::setData(const QModelIndex &index, const QVariant &value, int role )
{ 
   ...
   XianStruct newData = value.value<XianStruct>();
   ...
}

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Notice that you are passing a pointer but then you're expecting it to be a value.