Extjs grid 失去选中行的列数据

function getSelectedTableName() {
	var grid = Ext.getCmp('tempTableGridId');
	var rowSelectionModel = grid.getSelectionModel();
	if (rowSelectionModel.hasSelection()) {
		var record = rowSelectionModel.getSelected();
		var tableName = record.get('tableName');
		return tableName;
	} else {
		return '';
	}
}

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